{"id":"e2e15c63-a107-5e1d-9a6e-d4a67f7499e4","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:selective-mg-depletion-blunts-pth-calcitriol-response","predicate":"elicits-smaller-calcitriol-response-after-mg-depletion","statement":"The rise in circulating calcitriol during a six-hour human PTH(1-34) infusion was smaller after dietary Mg depletion.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"b4a8963f-8706-5591-babf-9210a34da19d","mechanism_event_label":"Even when PTH was supplied directly, the downstream vitamin-D response was reduced, supporting a target-organ component beyond reduced hormone release.","subject":{"id":"e162b0ab-1449-5471-b3c3-4638a0fa3a96","slug":"pth","display_name":"Parathyroid hormone / PTH","entity_type_key":"protein"},"object":{"id":"f5156c24-108f-5746-b114-ed764e79a3f4","slug":"calcitriol","display_name":"Calcitriol","entity_type_key":"small_molecule"},"evidence_count":1,"mechanism_event":{"id":"b4a8963f-8706-5591-babf-9210a34da19d","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:selective-mg-depletion-blunts-pth-calcitriol-response-event","event_type":"biochemical_relationship","label":"Even when PTH was supplied directly, the downstream vitamin-D response was reduced, supporting a target-organ component beyond reduced hormone release.","description":"The rise in circulating calcitriol during a six-hour human PTH(1-34) infusion was smaller after dietary Mg depletion.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"1f0c42f0-eaf3-5b86-966d-7ffc8a84872b","slug":"magnesium","display_name":"Magnesium","entity_type_key":"nutrient_element"},"role":"depleted nutrient","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"96b29e93-a2d1-56e7-84a3-2c5a61b4ee09","slug":"calcitriol-production","display_name":"Calcitriol production","entity_type_key":"cellular_process"},"role":"candidate downstream process, not directly measured","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"6ffdecce-6117-5eee-a1b2-f03a6fb6c272","slug":"pth1r","display_name":"Parathyroid hormone receptor 1 / PTH1R","entity_type_key":"protein"},"role":"receptor context","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"e162b0ab-1449-5471-b3c3-4638a0fa3a96","slug":"pth","display_name":"Parathyroid hormone / PTH","entity_type_key":"protein"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"f5156c24-108f-5746-b114-ed764e79a3f4","slug":"calcitriol","display_name":"Calcitriol","entity_type_key":"small_molecule"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"cross_nutrient","value_text":"magnesium -> PTH response -> vitamin D/calcium","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"26 initially normal adults before/after three-week low-Mg diet","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Circulating metabolite response does not identify CYP27B1 as a directly Mg-dependent enzyme or distinguish all production/clearance effects.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Magnesium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"magnesium","display_name":"Magnesium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Even when PTH was supplied directly, the downstream vitamin-D response was reduced, supporting a target-organ component beyond reduced hormone release.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[fatemi-1991-selective-depletion] Effect of experimental human magnesium depletion on parathyroid hormone secretion and 1,25-dihydroxyvitamin D metabolism. (1991). https://pubmed.ncbi.nlm.nih.gov/1939521/ DOI: 10.1210/jcem-73-5-1067","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Blood; parathyroid and renal mineral axis","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"97adb36e-2ce7-567b-aba5-e735b5295273","evidence_kind":"source_excerpt","locator":"Lines 385-395","start_line":385,"end_line":395,"excerpt":"### selective-mg-depletion-blunts-pth-calcitriol-response\nThe rise in circulating calcitriol during a six-hour human PTH(1-34) infusion was smaller after dietary Mg depletion.\nCondition category: nutrient_deficiency\nnutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Even when PTH was supplied directly, the downstream vitamin-D response was reduced, supporting a target-organ component beyond reduced hormone release.\norganism: Homo sapiens\ntissue_or_cell_type: Blood; parathyroid and renal mineral axis\nexperimental_model: 26 initially normal adults before/after three-week low-Mg diet\nlimitations: Circulating metabolite response does not identify CYP27B1 as a directly Mg-dependent enzyme or distinguish all production/clearance effects.\ncross_nutrient: magnesium -> PTH response -> vitamin D/calcium\n[fatemi-1991-selective-depletion] Effect of experimental human magnesium depletion on parathyroid hormone secretion and 1,25-dihydroxyvitamin D metabolism. (1991). https://pubmed.ncbi.nlm.nih.gov/1939521/ DOI: 10.1210/jcem-73-5-1067","model_system":"26 initially normal adults before/after three-week low-Mg diet","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [fatemi-1991-selective-depletion] Effect of experimental human magnesium depletion on parathyroid hormone secretion and 1,25-dihydroxyvitamin D metabolism. (1991). https://pubmed.ncbi.nlm.nih.gov/1939521/ DOI: 10.1210/jcem-73-5-1067","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dd101e28-1a2e-5a48-9d1e-809c77514866","stable_key":"import-0f17db03-207f-5910-ac8e-13dfc2f378ce","title":"Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. 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