Component

Endothelial tetrahydrobiopterin concentration, species specified

Endothelial tetrahydrobiopterin concentration, species specified. Species, exposure and limitations are retained in each linked claim.

2 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What acts on it

  1. 5-MTHF increased vascular BH4 and its proportion of total biopterin in human vessel experiments.

    5-Methyltetrahydrofolate → Endothelial tetrahydrobiopterin concentration, species specified source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/citrulline-research/16940192.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "42c07dd0bbacfc1ff44f78d6ce69810a58946e53c76bf5d3bf8385db5278ba8b", "start_char": 0, "end_char": 1942, "text_sha256": "42c07dd0bbacfc1ff44f78d6ce69810a58946e53c76bf5d3bf8385db5278ba8b"}
    experimental_model
    Ex-vivo vessel exposure and randomized pre-harvest infusion
    exposure
    5-MTHF ex vivo 1-100 micromolar; intravenous 5-MTHF or placebo in a separate subset
    limitations
    Uses 5-MTHF and acute vessel endpoints; cannot be generalized to all folic-acid doses or combination supplements.
    nutrient_topic
    Citrulline research collection; topical membership is not evidence of a direct dietary effect. · L-Citrulline
    organism
    Human, vessels from 117 CABG patients
    plain_language
    A folate form affected availability of the NO-synthase cofactor.
    primary_references
    [citrulline-p16940192] 5-methyltetrahydrofolate rapidly improves endothelial function and decreases superoxide production in human vessels: effects on vascular tetrahydrobiopterin availability and endothelial nitric oxide synthase coupling. (2006). https://pubmed.ncbi.nlm.nih.gov/16940192/ DOI: 10.1161/circulationaha.106.612325
    tissue_or_cell_type
    Saphenous veins and internal mammary arteries

    Citrulline: arginine recycling, nitrogen disposal and nutrient connections (2026-09-17) · lines 736–747

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Ex-vivo vessel exposure and randomized pre-harvest infusion · source_derived_draft · unverified_draft

    ### citrulline-folate-bh4 5-MTHF increased vascular BH4 and its proportion of total biopterin in human vessel experiments. Condition category: normal nutrient_topic: Citrulline research collection; topical membership is not evidence of a direct dietary effect. plain_language: A folate form affected availability of the NO-synthase cofactor. organism: Human, vessels from 117 CABG patients tissue_or_cell_type: Saphenous veins and internal mammary arteries experimental_model: Ex-vivo vessel exposure and randomized pre-harvest infusion limitations: Uses 5-MTHF and acute vessel endpoints; cannot be generalized to all folic-acid doses or combination supplements. exposure: 5-MTHF ex vivo 1-100 micromolar; intravenous 5-MTHF or placebo in a separate subset evidence_span: {"source_cache": "artifacts/citrulline-research/16940192.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "42c07dd0bbacfc1ff44f78d6ce69810a58946e53c76bf5d3bf8385db5278ba8b", "start_char": 0, "end_char": 1942, "text_sha256": "42c07dd0bbacfc1ff44f78d6ce69810a58946e53c76bf5d3bf8385db5278ba8b"} [citrulline-p16940192] 5-methyltetrahydrofolate rapidly improves endothelial function and decreases superoxide production in human vessels: effects on vascular tetrahydrobiopterin availability and endothelial nitric oxide synthase coupling. (2006). https://pubmed.ncbi.nlm.nih.gov/16940192/ DOI: 10.1161/circulationaha.106.612325
    Complete structured claim and evidence

  2. Ascorbate increased intracellular BH4 in porcine aortic endothelial cells.

    L-Ascorbate → Endothelial tetrahydrobiopterin concentration, species specified source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/citrulline-research/10749876.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "10605941fa542bd62ed4ee0fb042ea7569f3ab619f1cb893b54d7e62386712ed", "start_char": 0, "end_char": 1519, "text_sha256": "10605941fa542bd62ed4ee0fb042ea7569f3ab619f1cb893b54d7e62386712ed"}
    experimental_model
    Cell exposure and recombinant-enzyme assays
    exposure
    Ascorbate loading; BH4 or sepiapterin comparisons
    limitations
    Preclinical experiments; not proof that vitamin C is needed as a co-supplement with citrulline.
    nutrient_topic
    Citrulline research collection; topical membership is not evidence of a direct dietary effect. · L-Citrulline
    organism
    Porcine aortic endothelial cells and bovine eNOS
    plain_language
    Vitamin C can affect cofactor availability in this cell model.
    primary_references
    [citrulline-p10749876] Ascorbic acid enhances endothelial nitric-oxide synthase activity by increasing intracellular tetrahydrobiopterin. (2000). https://pubmed.ncbi.nlm.nih.gov/10749876/ DOI: 10.1074/jbc.m002248200
    tissue_or_cell_type
    BH4 availability and NO bioactivity

    Citrulline: arginine recycling, nitrogen disposal and nutrient connections (2026-09-17) · lines 697–708

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cell exposure and recombinant-enzyme assays · source_derived_draft · unverified_draft

    ### citrulline-vitaminc-bh4 Ascorbate increased intracellular BH4 in porcine aortic endothelial cells. Condition category: normal nutrient_topic: Citrulline research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin C can affect cofactor availability in this cell model. organism: Porcine aortic endothelial cells and bovine eNOS tissue_or_cell_type: BH4 availability and NO bioactivity experimental_model: Cell exposure and recombinant-enzyme assays limitations: Preclinical experiments; not proof that vitamin C is needed as a co-supplement with citrulline. exposure: Ascorbate loading; BH4 or sepiapterin comparisons evidence_span: {"source_cache": "artifacts/citrulline-research/10749876.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "10605941fa542bd62ed4ee0fb042ea7569f3ab619f1cb893b54d7e62386712ed", "start_char": 0, "end_char": 1519, "text_sha256": "10605941fa542bd62ed4ee0fb042ea7569f3ab619f1cb893b54d7e62386712ed"} [citrulline-p10749876] Ascorbic acid enhances endothelial nitric-oxide synthase activity by increasing intracellular tetrahydrobiopterin. (2000). https://pubmed.ncbi.nlm.nih.gov/10749876/ DOI: 10.1074/jbc.m002248200
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

    Evidence, AI assistance and curation standards