Trivalent chromium / Cr(III)

evidence_span

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experimental_model

Isolated rat insulin receptor and adipocyte membrane kinase assays

exposure

Insulin activation with added low-molecular-weight chromium-binding material

limitations

Assay activity is distinct from proof of an endogenous human cofactor. The peptide preparation and its cellular origin remain disputed; chromium is not shown to be an obligatory catalytic metal of INSR.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat receptor; isolated chromium oligopeptide preparation

plain_language

Removing the preparation’s metal content reduced its assay effect; that does not establish dietary chromium deficiency in humans.

primary_references

[chromium-p9109644] Chromium oligopeptide activates insulin receptor tyrosine kinase activity. (1997). https://pubmed.ncbi.nlm.nih.gov/9109644/ DOI: 10.1021/bi963154t

tissue_or_cell_type

Purified receptor and membrane fragments

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 276–287

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Isolated rat insulin receptor and adipocyte membrane kinase assays · source_derived_draft · unverified_draft

### chromium-chromodulin-metal-dependence The preparation’s ability to enhance insulin-receptor tyrosine-kinase activity depended on its chromium content. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Removing the preparation’s metal content reduced its assay effect; that does not establish dietary chromium deficiency in humans. organism: Rat receptor; isolated chromium oligopeptide preparation tissue_or_cell_type: Purified receptor and membrane fragments experimental_model: Isolated rat insulin receptor and adipocyte membrane kinase assays limitations: Assay activity is distinct from proof of an endogenous human cofactor. The peptide preparation and its cellular origin remain disputed; chromium is not shown to be an obligatory catalytic metal of INSR. exposure: Insulin activation with added low-molecular-weight chromium-binding material evidence_span: {"source_cache": "artifacts/chromium-research/9109644.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "23e955cef071c135f3935f440f4e333d49f494f004ceb22574df717c86bb7283", "start_char": 0, "end_char": 939, "text_sha256": "23e955cef071c135f3935f440f4e333d49f494f004ceb22574df717c86bb7283"} [chromium-p9109644] Chromium oligopeptide activates insulin receptor tyrosine kinase activity. (1997). https://pubmed.ncbi.nlm.nih.gov/9109644/ DOI: 10.1021/bi963154t

evidence_span

{"source_cache": "artifacts/chromium-research/36662348.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "500f334d72ca34561016a11f0c3bf866998ee364085855e54a2f29025bc916a8", "start_char": 0, "end_char": 1155, "text_sha256": "500f334d72ca34561016a11f0c3bf866998ee364085855e54a2f29025bc916a8"}

experimental_model

Characterization of pre-reacted chromium-ligand preparations and DNA-binding assays

exposure

Pre-reacted chromium cysteinate, chromium glutathione and chromium ascorbate preparations

limitations

These preparation-specific results challenge earlier assignments but do not show that Cr(VI) is harmless or directly reproduce every reductive chromate-DNA reaction.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Cell-free chemistry

plain_language

Pre-forming a metal complex can give a different result from reducing chromate in the presence of DNA; the claimed lesion identity needs checking.

primary_references

[chromium-p36662348] Examining the Potential Formation of Ternary DNA Complexes with Chromium‑Cysteine, Chromium-Ascorbate, and Chromium-Glutathione and Implications for Their Carcinogenicity. (2023). https://pubmed.ncbi.nlm.nih.gov/36662348/ DOI: 10.1007/s12011-023-03573-8

tissue_or_cell_type

Defined chromium complexes and DNA

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 1186–1197

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Characterization of pre-reacted chromium-ligand preparations and DNA-binding assays · source_derived_draft · unverified_draft

### chromium-prereacted-dna-binding-null The characterized pre-reacted Cr(III)-cysteine, -glutathione and -ascorbate preparations did not measurably bind DNA or form the proposed ternary adducts under the tested conditions. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Pre-forming a metal complex can give a different result from reducing chromate in the presence of DNA; the claimed lesion identity needs checking. organism: Cell-free chemistry tissue_or_cell_type: Defined chromium complexes and DNA experimental_model: Characterization of pre-reacted chromium-ligand preparations and DNA-binding assays limitations: These preparation-specific results challenge earlier assignments but do not show that Cr(VI) is harmless or directly reproduce every reductive chromate-DNA reaction. exposure: Pre-reacted chromium cysteinate, chromium glutathione and chromium ascorbate preparations evidence_span: {"source_cache": "artifacts/chromium-research/36662348.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "500f334d72ca34561016a11f0c3bf866998ee364085855e54a2f29025bc916a8", "start_char": 0, "end_char": 1155, "text_sha256": "500f334d72ca34561016a11f0c3bf866998ee364085855e54a2f29025bc916a8"} [chromium-p36662348] Examining the Potential Formation of Ternary DNA Complexes with Chromium‑Cysteine, Chromium-Ascorbate, and Chromium-Glutathione and Implications for Their Carcinogenicity. (2023). https://pubmed.ncbi.nlm.nih.gov/36662348/ DOI: 10.1007/s12011-023-03573-8

evidence_span

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experimental_model

Vascularly perfused small-intestine preparation

exposure

Inorganic Cr(III) 0.2–20 µmol/L; chromium-adequate diet before preparation

limitations

Nonsaturability supports passive uptake under this preparation; it does not identify a human transporter or cover all supplement complexes.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat

plain_language

This rat preparation did not show a saturable uptake system over the tested range.

primary_references

[chromium-p2778539] Absorption of inorganic, trivalent chromium from the vascularly perfused rat small intestine. (1989). https://pubmed.ncbi.nlm.nih.gov/2778539/ DOI: 10.1093/jn/119.8.1138

tissue_or_cell_type

Intestinal lumen, wall and vascular perfusate

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 94–105

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Vascularly perfused small-intestine preparation · source_derived_draft · unverified_draft

### chromium-rat-intestinal-uptake Cr(III) uptake and vascular transfer were nonsaturable across 0.2–20 µmol/L in the perfused rat intestine; the authors interpreted the behavior as passive diffusion. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: This rat preparation did not show a saturable uptake system over the tested range. organism: Rat tissue_or_cell_type: Intestinal lumen, wall and vascular perfusate experimental_model: Vascularly perfused small-intestine preparation limitations: Nonsaturability supports passive uptake under this preparation; it does not identify a human transporter or cover all supplement complexes. exposure: Inorganic Cr(III) 0.2–20 µmol/L; chromium-adequate diet before preparation evidence_span: {"source_cache": "artifacts/chromium-research/2778539.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1c3f4249245a1ed57e89179e1f751a537e52fe566de25a9859833895553d2e0e", "start_char": 0, "end_char": 1379, "text_sha256": "1c3f4249245a1ed57e89179e1f751a537e52fe566de25a9859833895553d2e0e"} [chromium-p2778539] Absorption of inorganic, trivalent chromium from the vascularly perfused rat small intestine. (1989). https://pubmed.ncbi.nlm.nih.gov/2778539/ DOI: 10.1093/jn/119.8.1138

evidence_span

{"source_cache": "artifacts/chromium-research/9056266.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06", "start_char": 0, "end_char": 791, "text_sha256": "36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06"}

experimental_model

Isolation and spectroscopy of a bovine-liver chromium-containing peptide fraction

exposure

Spectroscopic characterization of an isolate with approximately four Cr(III) ions per peptide

limitations

The paper interpreted the isolate as naturally occurring; later work questioned whether similar low-molecular-weight species arise during extraction. Exact nuclearity was not resolved by this study.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Bovine liver isolate

plain_language

Researchers isolated a chromium-binding peptide fraction, but its structure and origin inside living cells were not fully settled.

primary_references

[chromium-p9056266] Isolation and characterization of a biologically active chromium oligopeptide from bovine liver. (1997). https://pubmed.ncbi.nlm.nih.gov/9056266/ DOI: 10.1006/abbi.1997.9878

tissue_or_cell_type

Purified fraction outside intact cells

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 224–235

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Isolation and spectroscopy of a bovine-liver chromium-containing peptide fraction · source_derived_draft · unverified_draft

### chromium-chromodulin-isolate The bovine-liver low-molecular-weight isolate contained approximately four Cr(III) ions per peptide, with spectra consistent with carboxylate-supported metal assemblies; one tetranuclear versus two dinuclear assemblies was unresolved. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Researchers isolated a chromium-binding peptide fraction, but its structure and origin inside living cells were not fully settled. organism: Bovine liver isolate tissue_or_cell_type: Purified fraction outside intact cells experimental_model: Isolation and spectroscopy of a bovine-liver chromium-containing peptide fraction limitations: The paper interpreted the isolate as naturally occurring; later work questioned whether similar low-molecular-weight species arise during extraction. Exact nuclearity was not resolved by this study. exposure: Spectroscopic characterization of an isolate with approximately four Cr(III) ions per peptide evidence_span: {"source_cache": "artifacts/chromium-research/9056266.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06", "start_char": 0, "end_char": 791, "text_sha256": "36be61aa6271d3491a4432d31d5ea6524a059fcc1f1ba1e0acac5f175f711a06"} [chromium-p9056266] Isolation and characterization of a biologically active chromium oligopeptide from bovine liver. (1997). https://pubmed.ncbi.nlm.nih.gov/9056266/ DOI: 10.1006/abbi.1997.9878

evidence_span

{"source_cache": "artifacts/chromium-research/32650146.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "826e2d7f86ec2016d526ca8a8858db0249f4797aad842189d7f0359b6f375f85", "start_char": 0, "end_char": 1004, "text_sha256": "826e2d7f86ec2016d526ca8a8858db0249f4797aad842189d7f0359b6f375f85"}

experimental_model

X-ray crystallography of chromium-loaded transferrin

exposure

Cr(III)-transferrin crystallized with malonate as the synergistic anion

limitations

Crystal ligands and occupancy depend on preparation; malonate is not evidence that every circulating complex has the same coordination environment.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Human serum transferrin

plain_language

The iron-carrier protein can bind chromium in a structurally characterized pocket.

primary_references

[chromium-p32650146] X-ray structure of chromium(III)-containing transferrin: First structure of a physiological Cr(III)-binding protein. (2020). https://pubmed.ncbi.nlm.nih.gov/32650146/ DOI: 10.1016/j.jinorgbio.2020.111101

tissue_or_cell_type

Protein crystals

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 146–157

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · X-ray crystallography of chromium-loaded transferrin · source_derived_draft · unverified_draft

### chromium-transferrin-crystal Cr(III)-transferrin crystals contained a chromium-loaded closed C-terminal lobe and an open empty N-terminal lobe; two tyrosines, histidine, aspartate and chelating malonate coordinated the metal. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The iron-carrier protein can bind chromium in a structurally characterized pocket. organism: Human serum transferrin tissue_or_cell_type: Protein crystals experimental_model: X-ray crystallography of chromium-loaded transferrin limitations: Crystal ligands and occupancy depend on preparation; malonate is not evidence that every circulating complex has the same coordination environment. exposure: Cr(III)-transferrin crystallized with malonate as the synergistic anion evidence_span: {"source_cache": "artifacts/chromium-research/32650146.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "826e2d7f86ec2016d526ca8a8858db0249f4797aad842189d7f0359b6f375f85", "start_char": 0, "end_char": 1004, "text_sha256": "826e2d7f86ec2016d526ca8a8858db0249f4797aad842189d7f0359b6f375f85"} [chromium-p32650146] X-ray structure of chromium(III)-containing transferrin: First structure of a physiological Cr(III)-binding protein. (2020). https://pubmed.ncbi.nlm.nih.gov/32650146/ DOI: 10.1016/j.jinorgbio.2020.111101

evidence_span

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experimental_model

Purified human transferrin release kinetics and soluble receptor interaction

exposure

pH 4.5 and 5.5; weak/tight binding sites; biological chelators and soluble transferrin receptor

limitations

The study establishes release kinetics, not the entire in-vivo pathway. The molecular route from the endosomal lumen to cytosol remains unresolved.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Human proteins in vitro

plain_language

Acidification helps release chromium from its carrier, with different behavior at the two sites.

primary_references

[chromium-p31669693] Release of trivalent chromium from serum transferrin is sufficiently rapid to be physiologically relevant. (2020). https://pubmed.ncbi.nlm.nih.gov/31669693/ DOI: 10.1016/j.jinorgbio.2019.110901

tissue_or_cell_type

Endosome-mimicking solution

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 159–170

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human transferrin release kinetics and soluble receptor interaction · source_derived_draft · unverified_draft

### chromium-acidic-release Acidic pH promoted rapid Cr(III) release from the weak transferrin site; release from the tighter site was slower and depended on the chelating environment. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Acidification helps release chromium from its carrier, with different behavior at the two sites. organism: Human proteins in vitro tissue_or_cell_type: Endosome-mimicking solution experimental_model: Purified human transferrin release kinetics and soluble receptor interaction limitations: The study establishes release kinetics, not the entire in-vivo pathway. The molecular route from the endosomal lumen to cytosol remains unresolved. exposure: pH 4.5 and 5.5; weak/tight binding sites; biological chelators and soluble transferrin receptor evidence_span: {"source_cache": "artifacts/chromium-research/31669693.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835", "start_char": 0, "end_char": 1635, "text_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835"} [chromium-p31669693] Release of trivalent chromium from serum transferrin is sufficiently rapid to be physiologically relevant. (2020). https://pubmed.ncbi.nlm.nih.gov/31669693/ DOI: 10.1016/j.jinorgbio.2019.110901

evidence_span

{"source_cache": "artifacts/chromium-research/17263387.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35", "start_char": 0, "end_char": 1638, "text_sha256": "912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35"}

experimental_model

X-ray absorption and EPR before and after cell fractionation

exposure

Cr(VI)-treated cells; comparisons with model Cr(III) complexes

limitations

The artifact evidence concerns chromium(VI)-exposed cells and the tested isolation procedures. It does not negate the activity measured when an isolated peptide preparation is added to an enzyme assay.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Human A549/HepG2, hamster V79 and mouse C2C12 cells

plain_language

Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal.

primary_references

[chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r

tissue_or_cell_type

Intact and lysed cell preparations

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 237–248

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · X-ray absorption and EPR before and after cell fractionation · source_derived_draft · unverified_draft

### chromium-chromodulin-isolation-artifact Most Cr(III) formed in Cr(VI)-treated cells was associated with high-molecular-mass ligands; cell lysis redistributed chromium into a low-molecular-weight fraction spectroscopically similar to reported chromodulin. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Some apparent chromodulin-like material formed during sample preparation, raising doubts about its identity as a pre-existing cellular signal. organism: Human A549/HepG2, hamster V79 and mouse C2C12 cells tissue_or_cell_type: Intact and lysed cell preparations experimental_model: X-ray absorption and EPR before and after cell fractionation limitations: The artifact evidence concerns chromium(VI)-exposed cells and the tested isolation procedures. It does not negate the activity measured when an isolated peptide preparation is added to an enzyme assay. exposure: Cr(VI)-treated cells; comparisons with model Cr(III) complexes evidence_span: {"source_cache": "artifacts/chromium-research/17263387.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35", "start_char": 0, "end_char": 1638, "text_sha256": "912905b2fefe0745017faae62124fe077d3944cde635ae1012ff76fc33094b35"} [chromium-p17263387] X-ray absorption and EPR spectroscopic studies of the biotransformations of chromium(VI) in mammalian cells. Is chromodulin an artifact of isolation methods? (2007). https://pubmed.ncbi.nlm.nih.gov/17263387/ DOI: 10.1021/ja063792r

availability_state

machinery_impairment Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/chromium-research/27592288.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "541c9ba554cad6d899569dc16cdd68b1125542e2df006cb50db19f66d6e78d09", "start_char": 0, "end_char": 1460, "text_sha256": "541c9ba554cad6d899569dc16cdd68b1125542e2df006cb50db19f66d6e78d09"}

experimental_model

Transferrin incubation, metal binding and rat delivery experiments

exposure

Transferrin stored at 37°C with or without glucose before chromium binding and delivery assays

limitations

Protein storage itself altered binding. The glycated-protein result does not establish chromium deficiency in human diabetes or a treatment response.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Purified transferrin and rat in-vivo transport

plain_language

A carrier can still bind the metal yet distribute it less effectively.

primary_references

[chromium-p27592288] The effects of the glycation of transferrin on chromium binding and the transport and distribution of chromium in vivo. (2016). https://pubmed.ncbi.nlm.nih.gov/27592288/ DOI: 10.1016/j.jinorgbio.2016.08.008

tissue_or_cell_type

Carrier protein and systemic chromium distribution

trigger_kind

machinery_impairment Imported condition classification; unverified.

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 471–482

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Transferrin incubation, metal binding and rat delivery experiments · source_derived_draft · unverified_draft

### chromium-glycated-transferrin-delivery Glycated transferrin retained two chromium-binding equivalents but had altered spectroscopic behavior and greatly reduced chromium delivery in rats. Condition category: machinery_impairment nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: A carrier can still bind the metal yet distribute it less effectively. organism: Purified transferrin and rat in-vivo transport tissue_or_cell_type: Carrier protein and systemic chromium distribution experimental_model: Transferrin incubation, metal binding and rat delivery experiments limitations: Protein storage itself altered binding. The glycated-protein result does not establish chromium deficiency in human diabetes or a treatment response. exposure: Transferrin stored at 37°C with or without glucose before chromium binding and delivery assays evidence_span: {"source_cache": "artifacts/chromium-research/27592288.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "541c9ba554cad6d899569dc16cdd68b1125542e2df006cb50db19f66d6e78d09", "start_char": 0, "end_char": 1460, "text_sha256": "541c9ba554cad6d899569dc16cdd68b1125542e2df006cb50db19f66d6e78d09"} [chromium-p27592288] The effects of the glycation of transferrin on chromium binding and the transport and distribution of chromium in vivo. (2016). https://pubmed.ncbi.nlm.nih.gov/27592288/ DOI: 10.1016/j.jinorgbio.2016.08.008

evidence_span

{"source_cache": "artifacts/chromium-research/18808157.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ed2c80b5da41d110da38bc0ed29d900d1d33f4180b64e13cb9b24ae7da5e1cdb", "start_char": 0, "end_char": 1724, "text_sha256": "ed2c80b5da41d110da38bc0ed29d900d1d33f4180b64e13cb9b24ae7da5e1cdb"}

experimental_model

Cell-free chromate reduction followed by plasmid replication in human fibroblasts

exposure

2 versus 5 mM glutathione with Cr(VI)

limitations

Toxicology assay, not oral chromium exposure. Proposed crosslink identities depend on preparation and analytical methods; later work questions some pre-reacted ternary-adduct preparations.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Chemical system with human fibroblast mutagenicity readout

plain_language

The authors detected and assigned a glutathione-linked DNA lesion; the preparation and analytical assignment matter.

primary_references

[chromium-p18808157] Reduction with glutathione is a weakly mutagenic pathway in chromium(VI) metabolism. (2008). https://pubmed.ncbi.nlm.nih.gov/18808157/ DOI: 10.1021/tx800265g

tissue_or_cell_type

DNA reaction mixture and reporter plasmid

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 1173–1184

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cell-free chromate reduction followed by plasmid replication in human fibroblasts · source_derived_draft · unverified_draft

### chromium-gsh-chromate-adducts The study attributed about 5% of total chromium-DNA adducts to GSH-Cr-DNA crosslinks at 2 mM glutathione, with four- to fivefold higher crosslinking at 5 mM. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The authors detected and assigned a glutathione-linked DNA lesion; the preparation and analytical assignment matter. organism: Chemical system with human fibroblast mutagenicity readout tissue_or_cell_type: DNA reaction mixture and reporter plasmid experimental_model: Cell-free chromate reduction followed by plasmid replication in human fibroblasts limitations: Toxicology assay, not oral chromium exposure. Proposed crosslink identities depend on preparation and analytical methods; later work questions some pre-reacted ternary-adduct preparations. exposure: 2 versus 5 mM glutathione with Cr(VI) evidence_span: {"source_cache": "artifacts/chromium-research/18808157.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "ed2c80b5da41d110da38bc0ed29d900d1d33f4180b64e13cb9b24ae7da5e1cdb", "start_char": 0, "end_char": 1724, "text_sha256": "ed2c80b5da41d110da38bc0ed29d900d1d33f4180b64e13cb9b24ae7da5e1cdb"} [chromium-p18808157] Reduction with glutathione is a weakly mutagenic pathway in chromium(VI) metabolism. (2008). https://pubmed.ncbi.nlm.nih.gov/18808157/ DOI: 10.1021/tx800265g

evidence_span

{"source_cache": "artifacts/chromium-research/8605085.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889", "start_char": 0, "end_char": 1103, "text_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889"}

experimental_model

Oral radiotracer retention and distribution experiments

exposure

Labeled oral chromium with dietary/metabolite coadministration

limitations

A negative retention result in this preparation does not exclude all chemical complexation or dose effects. Oral coadministration is not identical to a preformed chromium-nicotinate complex.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat

plain_language

Adding glutathione did not make the rats retain more chromium in this experiment.

primary_references

[chromium-p8605085] Dietary and metabolite effects on trivalent chromium retention and distribution in rats. (1995). https://pubmed.ncbi.nlm.nih.gov/8605085/ DOI: 10.1007/bf02789412

tissue_or_cell_type

Whole-body and tissue chromium

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 874–885

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Oral radiotracer retention and distribution experiments · source_derived_draft · unverified_draft

### chromium-gsh-retention-null Oral coadministration of glutathione with labeled chromium did not significantly alter chromium retention in the rat study. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding glutathione did not make the rats retain more chromium in this experiment. organism: Rat tissue_or_cell_type: Whole-body and tissue chromium experimental_model: Oral radiotracer retention and distribution experiments limitations: A negative retention result in this preparation does not exclude all chemical complexation or dose effects. Oral coadministration is not identical to a preformed chromium-nicotinate complex. exposure: Labeled oral chromium with dietary/metabolite coadministration evidence_span: {"source_cache": "artifacts/chromium-research/8605085.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889", "start_char": 0, "end_char": 1103, "text_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889"} [chromium-p8605085] Dietary and metabolite effects on trivalent chromium retention and distribution in rats. (1995). https://pubmed.ncbi.nlm.nih.gov/8605085/ DOI: 10.1007/bf02789412

evidence_span

{"source_cache": "artifacts/chromium-research/11472024.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba", "start_char": 0, "end_char": 1224, "text_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba"}

experimental_model

In-vivo chromium tracing with insulin stimulation

exposure

Administered chromium with transferrin transport and insulin comparisons

limitations

Rat tracer findings do not establish a required human insulin-signaling cofactor. Identification of urinary chromodulin was tentative in the indexed abstract.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat

plain_language

An insulin signal changed chromium distribution in this rat experiment.

primary_references

[chromium-p11472024] The trail of chromium(III) in vivo from the blood to the urine: the roles of transferrin and chromodulin. (2001). https://pubmed.ncbi.nlm.nih.gov/11472024/ DOI: 10.1007/s007750100238

tissue_or_cell_type

Blood, tissues and urine

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 198–209

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · In-vivo chromium tracing with insulin stimulation · source_derived_draft · unverified_draft

### chromium-insulin-chromium-delivery Insulin stimulated transferrin-associated chromium transport from blood into rat tissues, with liver and kidneys prominent destinations. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: An insulin signal changed chromium distribution in this rat experiment. organism: Rat tissue_or_cell_type: Blood, tissues and urine experimental_model: In-vivo chromium tracing with insulin stimulation limitations: Rat tracer findings do not establish a required human insulin-signaling cofactor. Identification of urinary chromodulin was tentative in the indexed abstract. exposure: Administered chromium with transferrin transport and insulin comparisons evidence_span: {"source_cache": "artifacts/chromium-research/11472024.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba", "start_char": 0, "end_char": 1224, "text_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba"} [chromium-p11472024] The trail of chromium(III) in vivo from the blood to the urine: the roles of transferrin and chromodulin. (2001). https://pubmed.ncbi.nlm.nih.gov/11472024/ DOI: 10.1007/s007750100238

evidence_span

{"source_cache": "artifacts/chromium-research/11472024.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba", "start_char": 0, "end_char": 1224, "text_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba"}

experimental_model

In-vivo chromium tracing with insulin stimulation

exposure

Administered chromium with transferrin transport and insulin comparisons

limitations

Rat tracer findings do not establish a required human insulin-signaling cofactor. Identification of urinary chromodulin was tentative in the indexed abstract.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat

plain_language

The experiment links insulin exposure to chromium loss, but the identity and physiological role of the urinary complex need qualification.

primary_references

[chromium-p11472024] The trail of chromium(III) in vivo from the blood to the urine: the roles of transferrin and chromodulin. (2001). https://pubmed.ncbi.nlm.nih.gov/11472024/ DOI: 10.1007/s007750100238

tissue_or_cell_type

Blood, tissues and urine

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 211–222

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · In-vivo chromium tracing with insulin stimulation · source_derived_draft · unverified_draft

### chromium-insulin-urinary-chromium Insulin-associated urinary chromium loss increased alongside a low-molecular-weight fraction interpreted as probable chromodulin in the rat study. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The experiment links insulin exposure to chromium loss, but the identity and physiological role of the urinary complex need qualification. organism: Rat tissue_or_cell_type: Blood, tissues and urine experimental_model: In-vivo chromium tracing with insulin stimulation limitations: Rat tracer findings do not establish a required human insulin-signaling cofactor. Identification of urinary chromodulin was tentative in the indexed abstract. exposure: Administered chromium with transferrin transport and insulin comparisons evidence_span: {"source_cache": "artifacts/chromium-research/11472024.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba", "start_char": 0, "end_char": 1224, "text_sha256": "8760ddbb2dd372b94d71880c6c95441fb876ed2196b4f111988aae1244b3daba"} [chromium-p11472024] The trail of chromium(III) in vivo from the blood to the urine: the roles of transferrin and chromodulin. (2001). https://pubmed.ncbi.nlm.nih.gov/11472024/ DOI: 10.1007/s007750100238

evidence_span

{"source_cache": "artifacts/chromium-research/8605085.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889", "start_char": 0, "end_char": 1103, "text_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889"}

experimental_model

Oral radiotracer retention and distribution experiments

exposure

Labeled oral chromium with dietary/metabolite coadministration

limitations

A negative retention result in this preparation does not exclude all chemical complexation or dose effects. Oral coadministration is not identical to a preformed chromium-nicotinate complex.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Rat

plain_language

Adding nicotinic acid did not make the rats retain more chromium in this experiment.

primary_references

[chromium-p8605085] Dietary and metabolite effects on trivalent chromium retention and distribution in rats. (1995). https://pubmed.ncbi.nlm.nih.gov/8605085/ DOI: 10.1007/bf02789412

tissue_or_cell_type

Whole-body and tissue chromium

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 861–872

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Oral radiotracer retention and distribution experiments · source_derived_draft · unverified_draft

### chromium-niacin-retention-null Oral coadministration of nicotinic acid with labeled chromium did not significantly alter chromium retention in the rat study. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding nicotinic acid did not make the rats retain more chromium in this experiment. organism: Rat tissue_or_cell_type: Whole-body and tissue chromium experimental_model: Oral radiotracer retention and distribution experiments limitations: A negative retention result in this preparation does not exclude all chemical complexation or dose effects. Oral coadministration is not identical to a preformed chromium-nicotinate complex. exposure: Labeled oral chromium with dietary/metabolite coadministration evidence_span: {"source_cache": "artifacts/chromium-research/8605085.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889", "start_char": 0, "end_char": 1103, "text_sha256": "19976d36625bfcd29ba9739717e4b5ee7c2a641dc625a2bfed62947df7060889"} [chromium-p8605085] Dietary and metabolite effects on trivalent chromium retention and distribution in rats. (1995). https://pubmed.ncbi.nlm.nih.gov/8605085/ DOI: 10.1007/bf02789412

evidence_span

{"source_cache": "artifacts/chromium-research/31669693.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835", "start_char": 0, "end_char": 1635, "text_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835"}

experimental_model

Purified human transferrin release kinetics and soluble receptor interaction

exposure

pH 4.5 and 5.5; weak/tight binding sites; biological chelators and soluble transferrin receptor

limitations

The study establishes release kinetics, not the entire in-vivo pathway. The molecular route from the endosomal lumen to cytosol remains unresolved.

nutrient_topic

Chromium research collection; topical membership is not evidence of a direct dietary effect. · Chromium

organism

Human proteins in vitro

plain_language

The receptor changed the carrier’s behavior and helped it release chromium in this assay.

primary_references

[chromium-p31669693] Release of trivalent chromium from serum transferrin is sufficiently rapid to be physiologically relevant. (2020). https://pubmed.ncbi.nlm.nih.gov/31669693/ DOI: 10.1016/j.jinorgbio.2019.110901

tissue_or_cell_type

Endosome-mimicking solution

Chromium: transport, insulin signaling, nutrient interactions and essentiality debate (2026-09-17) · lines 172–183

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human transferrin release kinetics and soluble receptor interaction · source_derived_draft · unverified_draft

### chromium-receptor-accelerated-release Binding of chromium-loaded transferrin to soluble transferrin receptor accelerated chromium release from both sites at acidic pH. Condition category: normal nutrient_topic: Chromium research collection; topical membership is not evidence of a direct dietary effect. plain_language: The receptor changed the carrier’s behavior and helped it release chromium in this assay. organism: Human proteins in vitro tissue_or_cell_type: Endosome-mimicking solution experimental_model: Purified human transferrin release kinetics and soluble receptor interaction limitations: The study establishes release kinetics, not the entire in-vivo pathway. The molecular route from the endosomal lumen to cytosol remains unresolved. exposure: pH 4.5 and 5.5; weak/tight binding sites; biological chelators and soluble transferrin receptor evidence_span: {"source_cache": "artifacts/chromium-research/31669693.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835", "start_char": 0, "end_char": 1635, "text_sha256": "bdb962ff7838d36dfbc2cd2df4eed4e07c81ebd824c6e95096c5d7069ec32835"} [chromium-p31669693] Release of trivalent chromium from serum transferrin is sufficiently rapid to be physiologically relevant. (2020). https://pubmed.ncbi.nlm.nih.gov/31669693/ DOI: 10.1016/j.jinorgbio.2019.110901