Component
Calcitroic acid
Water-soluble side-chain-shortened acid formed during multistep calcitriol catabolism.
2 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
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.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
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.
What acts on it
Wild-type human CYP24A1 expressed in V79-4 cells metabolized calcitriol through C24-pathway intermediates to a water-soluble fraction assigned to calcitroic acid.
Experimental context and source evidence
- cross_nutrient
- false
- evidence_location
- Primary Results, in-vitro analysis and Figure 4; clinical cohorts and Discussion.
- experimental_model
- Human CYP24A1 expressed in V79-4 cells
- exposure
- Calcitriol 0.003-9 micromolar across transient/stable systems; Figure 4.
- limitations
- Aqueous radioactivity measures the terminal catabolic fraction; not every oxidation intermediate is individually isolated in this record.
- nutrient
- Vitamin D2 and D3 · Vitamin D2 and D3
- nutrient_topic
- Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin D2 and D3
- organism
- Homo sapiens protein in hamster-derived cells
- plain_language
- CYP24A1 carries active D3 through a multistep breakdown pathway.
- primary_references
- [schlingmann2011] Mutations in CYP24A1 and idiopathic infantile hypercalcemia. (2011). https://pubmed.ncbi.nlm.nih.gov/21675912/ DOI: 10.1056/NEJMoa1103864
- tissue_or_cell_type
- cellular vitamin D catabolic assay
Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 497–510
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CYP24A1 expressed in V79-4 cells · source_derived_draft · unverified_draft
### vd-act-cyp24a1-calcitroic Wild-type human CYP24A1 expressed in V79-4 cells metabolized calcitriol through C24-pathway intermediates to a water-soluble fraction assigned to calcitroic acid. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: CYP24A1 carries active D3 through a multistep breakdown pathway. organism: Homo sapiens protein in hamster-derived cells tissue_or_cell_type: cellular vitamin D catabolic assay experimental_model: Human CYP24A1 expressed in V79-4 cells limitations: Aqueous radioactivity measures the terminal catabolic fraction; not every oxidation intermediate is individually isolated in this record. exposure: Calcitriol 0.003-9 micromolar across transient/stable systems; Figure 4. cross_nutrient: false evidence_location: Primary Results, in-vitro analysis and Figure 4; clinical cohorts and Discussion. nutrient: Vitamin D2 and D3 [schlingmann2011] Mutations in CYP24A1 and idiopathic infantile hypercalcemia. (2011). https://pubmed.ncbi.nlm.nih.gov/21675912/ DOI: 10.1056/NEJMoa1103864
Complete structured claim and evidencePurified rat CYP24A1 produced a C24R-hydroxylated metabolite from active D2 but no detectable calcitroic acid under conditions that generated calcitroic acid from calcitriol.
Experimental context and source evidence
- cross_nutrient
- false
- evidence_location
- Primary abstract, purified-enzyme HPLC results.
- experimental_model
- Purified rat CYP24A1 with HPLC product analysis
- exposure
- Active D2 versus D3 substrates; detailed dose/time unavailable in abstract.
- limitations
- Negative detection is assay-specific. Rat enzyme behavior is not a claim that humans cannot metabolize D2 further.
- nutrient
- Vitamin D2 and D3 · Vitamin D2 and D3
- nutrient_topic
- Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin D2 and D3
- organism
- Rattus norvegicus protein
- plain_language
- A rat enzyme experiment found different terminal breakdown products for D2 and D3.
- primary_references
- [horst2003] Rat cytochrome P450C24 (CYP24) does not metabolize 1,25-dihydroxyvitamin D2 to calcitroic acid. (2003). https://pubmed.ncbi.nlm.nih.gov/12520527/ DOI: 10.1002/jcb.10359
- tissue_or_cell_type
- cell-free enzyme system
Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 572–585
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified rat CYP24A1 with HPLC product analysis · source_derived_draft · unverified_draft
### vd-act-rat-cyp24-d2-boundary Purified rat CYP24A1 produced a C24R-hydroxylated metabolite from active D2 but no detectable calcitroic acid under conditions that generated calcitroic acid from calcitriol. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: A rat enzyme experiment found different terminal breakdown products for D2 and D3. organism: Rattus norvegicus protein tissue_or_cell_type: cell-free enzyme system experimental_model: Purified rat CYP24A1 with HPLC product analysis limitations: Negative detection is assay-specific. Rat enzyme behavior is not a claim that humans cannot metabolize D2 further. exposure: Active D2 versus D3 substrates; detailed dose/time unavailable in abstract. cross_nutrient: false evidence_location: Primary abstract, purified-enzyme HPLC results. nutrient: Vitamin D2 and D3 [horst2003] Rat cytochrome P450C24 (CYP24) does not metabolize 1,25-dihydroxyvitamin D2 to calcitroic acid. (2003). https://pubmed.ncbi.nlm.nih.gov/12520527/ DOI: 10.1002/jcb.10359
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.