Component

Sodium-phosphate cotransporter NaPi-IIb / SLC34A2

Apical sodium-dependent phosphate cotransporter investigated in intestinal epithelial phosphate absorption.

4 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. A low-phosphate diet increased intestinal NaPi-IIb protein expression even in Vdr-null mice.

    Vdr-null mouse genotype → Sodium-phosphate cotransporter NaPi-IIb / SLC34A2 source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    cross_nutrient
    Vitamin D–calcium–phosphate regulation.
    evidence_locator
    Abstract: reported experimental results
    evidence_scope
    D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.
    experimental_model
    Vdr-null and wild-type mice; intestinal brush-border transporter immunodetection
    exposure
    Vdr deletion plus dietary phosphate restriction; exact dietary percentage and duration not given in the retrieved abstract.
    limitations
    Baseline NaPi-IIb protein and sodium-dependent phosphate transport were lower in knockout mice; preserved adaptation does not imply normal baseline transport.
    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
    Mus musculus
    plain_language
    The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling.
    primary_references
    [vdm-segawa2004] Intestinal Na-P(i) cotransporter adaptation to dietary P(i) content in vitamin D receptor null mice. (2004). https://pubmed.ncbi.nlm.nih.gov/14996670/ DOI: 10.1152/ajprenal.00375.2003
    tissue_or_cell_type
    Intestinal brush-border membrane
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 713–727

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Vdr-null and wild-type mice; intestinal brush-border transporter immunodetection · source_derived_draft · unverified_draft

    ### vdm-low-phosphate-adaptation-persists-without-vdr A low-phosphate diet increased intestinal NaPi-IIb protein expression even in Vdr-null mice. Condition category: machinery_impairment nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The intestine retained a phosphate-conservation response despite loss of vitamin D receptor signaling. organism: Mus musculus tissue_or_cell_type: Intestinal brush-border membrane experimental_model: Vdr-null and wild-type mice; intestinal brush-border transporter immunodetection limitations: Baseline NaPi-IIb protein and sodium-dependent phosphate transport were lower in knockout mice; preserved adaptation does not imply normal baseline transport. exposure: Vdr deletion plus dietary phosphate restriction; exact dietary percentage and duration not given in the retrieved abstract. cross_nutrient: Vitamin D–calcium–phosphate regulation. evidence_locator: Abstract: reported experimental results nutrient: Vitamin D2 and D3 evidence_scope: D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison. [vdm-segawa2004] Intestinal Na-P(i) cotransporter adaptation to dietary P(i) content in vitamin D receptor null mice. (2004). https://pubmed.ncbi.nlm.nih.gov/14996670/ DOI: 10.1152/ajprenal.00375.2003
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Two daily calcitriol injections increased active phosphate transport in wild-type mouse jejunum.

    Calcitriol → Active intestinal phosphate absorption source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Vitamin D–calcium–phosphate regulation.
    evidence_locator
    Abstract: reported experimental results
    evidence_scope
    D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.
    experimental_model
    Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays
    exposure
    Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract.
    limitations
    Stimulation was segment-specific: increased transporter protein in ileum did not establish the same active-flux response there. No human dietary-dose inference.
    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
    Mus musculus
    plain_language
    Active vitamin D increased the intestine’s sodium-coupled phosphate uptake in the responsive segment.
    primary_references
    [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    tissue_or_cell_type
    Jejunum

    Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 665–679

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays · source_derived_draft · unverified_draft

    ### vdm-calcitriol-increases-jejunal-phosphate-transport Two daily calcitriol injections increased active phosphate transport in wild-type mouse jejunum. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Active vitamin D increased the intestine’s sodium-coupled phosphate uptake in the responsive segment. organism: Mus musculus tissue_or_cell_type: Jejunum experimental_model: Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays limitations: Stimulation was segment-specific: increased transporter protein in ileum did not establish the same active-flux response there. No human dietary-dose inference. exposure: Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract. cross_nutrient: Vitamin D–calcium–phosphate regulation. evidence_locator: Abstract: reported experimental results nutrient: Vitamin D2 and D3 evidence_scope: D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison. [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    Complete structured claim and evidence

  2. The two-day calcitriol regimen did not detectably increase paracellular phosphate flux in the mouse intestine.

    Calcitriol → Paracellular intestinal phosphate flux source_derived_draftungraded
    Experimental context and source evidence
    cross_nutrient
    Vitamin D–calcium–phosphate regulation.
    evidence_locator
    Abstract: reported experimental results
    evidence_scope
    D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.
    experimental_model
    Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays
    exposure
    Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract.
    limitations
    A negative result for this assay and regimen does not exclude other doses, durations, species or intestinal segments.
    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
    Mus musculus
    plain_language
    The measured phosphate response involved transport through cells; the route between cells did not show the same increase.
    primary_references
    [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    tissue_or_cell_type
    Intestinal epithelium

    Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 681–695

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays · source_derived_draft · unverified_draft

    ### vdm-calcitriol-no-detected-paracellular-phosphate-response The two-day calcitriol regimen did not detectably increase paracellular phosphate flux in the mouse intestine. Condition category: normal nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: The measured phosphate response involved transport through cells; the route between cells did not show the same increase. organism: Mus musculus tissue_or_cell_type: Intestinal epithelium experimental_model: Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays limitations: A negative result for this assay and regimen does not exclude other doses, durations, species or intestinal segments. exposure: Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract. cross_nutrient: Vitamin D–calcium–phosphate regulation. evidence_locator: Abstract: reported experimental results nutrient: Vitamin D2 and D3 evidence_scope: D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison. [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    Complete structured claim and evidence

  3. Intestine-specific Slc34a2 deletion eliminated the phosphate-transport increase induced by the tested calcitriol regimen.

    Intestine-specific Slc34a2-null mouse genotype → Active intestinal phosphate absorption source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    cross_nutrient
    Vitamin D–calcium–phosphate regulation.
    evidence_locator
    Abstract: reported experimental results
    evidence_scope
    D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison.
    experimental_model
    Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays
    exposure
    Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract.
    limitations
    Conditional transporter loss removes the measured hormonal increment; it does not prove that all baseline phosphate absorption is absent.
    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
    Mus musculus
    plain_language
    Without this intestinal transporter, active vitamin D failed to produce its usual phosphate-uptake increment.
    primary_references
    [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    tissue_or_cell_type
    Intestinal epithelium
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 697–711

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays · source_derived_draft · unverified_draft

    ### vdm-slc34a2-deletion-removes-calcitriol-phosphate-increment Intestine-specific Slc34a2 deletion eliminated the phosphate-transport increase induced by the tested calcitriol regimen. Condition category: machinery_impairment nutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Without this intestinal transporter, active vitamin D failed to produce its usual phosphate-uptake increment. organism: Mus musculus tissue_or_cell_type: Intestinal epithelium experimental_model: Wild-type and intestinal Slc34a2-deleted mice; active versus paracellular intestinal phosphate transport assays limitations: Conditional transporter loss removes the measured hormonal increment; it does not prove that all baseline phosphate absorption is absent. exposure: Intraperitoneal calcitriol once daily for 2 days; dose not specified in the retrieved abstract. cross_nutrient: Vitamin D–calcium–phosphate regulation. evidence_locator: Abstract: reported experimental results nutrient: Vitamin D2 and D3 evidence_scope: D3 active metabolite or VDR machinery experiment; not a direct D2-versus-D3 comparison. [vdm-hernando2021] 1,25(OH)2 vitamin D3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. (2021). https://pubmed.ncbi.nlm.nih.gov/33200827/ DOI: 10.1113/jp280345
    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