{"id":"f4abbe45-e346-50d2-960c-1ed9708ee549","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:fgf23-reduces-cyp27b1-expression","predicate":"reduces_expression","statement":"Recombinant FGF23 lowers renal CYP27B1 mRNA before the fall in serum phosphate.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"2c9d083f-fbd0-5b84-9b96-9593966cc7dc","mechanism_event_label":"FGF23 restrains a vitamin D activation enzyme.","subject":{"id":"6edbc5a6-fcb5-516d-9c86-66950a8984b3","slug":"fgf23","display_name":"Fibroblast growth factor 23 / FGF23","entity_type_key":"protein"},"object":{"id":"a1d0238c-7529-5175-b5f9-71dc9bc61ed5","slug":"cyp27b1","display_name":"Vitamin D 1-alpha-hydroxylase / CYP27B1","entity_type_key":"protein"},"evidence_count":1,"mechanism_event":{"id":"2c9d083f-fbd0-5b84-9b96-9593966cc7dc","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:fgf23-reduces-cyp27b1-expression-event","event_type":"biochemical_relationship","label":"FGF23 restrains a vitamin D activation enzyme.","description":"Recombinant FGF23 lowers renal CYP27B1 mRNA before the fall in serum phosphate.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6edbc5a6-fcb5-516d-9c86-66950a8984b3","slug":"fgf23","display_name":"Fibroblast growth factor 23 / FGF23","entity_type_key":"protein"},"role":"hormone","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"a1d0238c-7529-5175-b5f9-71dc9bc61ed5","slug":"cyp27b1","display_name":"Vitamin D 1-alpha-hydroxylase / CYP27B1","entity_type_key":"protein"},"role":"regulated_enzyme","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"f5156c24-108f-5746-b114-ed764e79a3f4","slug":"calcitriol","display_name":"Calcitriol","entity_type_key":"small_molecule"},"role":"downstream_hormone","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"experimental_model","value_text":"Recombinant FGF23 injections in normal and parathyroidectomized rodents","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Injection study; transcript change is not direct enzyme inhibition.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Calcium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Mus musculus; Rattus norvegicus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"FGF23 restrains a vitamin D activation enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[shimada2004injection] FGF-23 is a potent regulator of vitamin D metabolism and phosphate homeostasis (2004). https://pubmed.ncbi.nlm.nih.gov/15040831/ DOI: 10.1359/JBMR.0301264","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Kidney","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"cf4447d3-b929-55b1-a26e-6ee2cc865586","evidence_kind":"source_excerpt","locator":"Lines 91-100","start_line":91,"end_line":100,"excerpt":"### fgf23-reduces-cyp27b1-expression\nRecombinant FGF23 lowers renal CYP27B1 mRNA before the fall in serum phosphate.\nCondition category: normal\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: FGF23 restrains a vitamin D activation enzyme.\norganism: Mus musculus; Rattus norvegicus\ntissue_or_cell_type: Kidney\nexperimental_model: Recombinant FGF23 injections in normal and parathyroidectomized rodents\nlimitations: Injection study; transcript change is not direct enzyme inhibition.\n[shimada2004injection] FGF-23 is a potent regulator of vitamin D metabolism and phosphate homeostasis (2004). https://pubmed.ncbi.nlm.nih.gov/15040831/ DOI: 10.1359/JBMR.0301264","model_system":"Recombinant FGF23 injections in normal and parathyroidectomized rodents","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [shimada2004injection] FGF-23 is a potent regulator of vitamin D metabolism and phosphate homeostasis (2004). https://pubmed.ncbi.nlm.nih.gov/15040831/ DOI: 10.1359/JBMR.0301264","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"3c083fa0-59c6-50e9-af42-678d0e3c1006","stable_key":"import-434e1e27-eb90-583a-956b-62472726ffba","title":"Calcium: mechanism-first literature curation (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"965c934d6b147f2b62f8d45ce6d7a87681a600bfe5c46a585b4704889afd3fc1","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}