{"id":"f8209857-a683-50dc-9bba-caff74fa1c1d","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-deficient-carnitine-excretion","predicate":"deficiency-increases","statement":"Without carnitine-precursor supplements, vitamin-C-deficient guinea pigs excreted approximately three times as much free and total carnitine as replete animals on days 19–28; pair feeding alone did not produce that pattern.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"fa4cd241-585e-5288-90fc-80275cf52037","mechanism_event_label":"Greater loss in urine can contribute to low carnitine during vitamin C deficiency.","subject":{"id":"da1a7137-08f2-5a36-8bb6-377fbd32e327","slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"},"object":{"id":"d7508505-8a1e-5bd1-9e23-05042800a967","slug":"guinea-pig-urinary-carnitine-excretion","display_name":"Guinea-pig urinary carnitine excretion","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"fa4cd241-585e-5288-90fc-80275cf52037","stable_key":"cb568d28-484a-5c2e-9fcc-2d780358e514:vc-enzyme-deficient-carnitine-excretion-event","event_type":"observed_intervention","label":"Greater loss in urine can contribute to low carnitine during vitamin C deficiency.","description":"Without carnitine-precursor supplements, vitamin-C-deficient guinea pigs excreted approximately three times as much free and total carnitine as replete animals on days 19–28; pair feeding alone did not produce that pattern.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"da1a7137-08f2-5a36-8bb6-377fbd32e327","slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"},"role":"dietary-factor","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"6e34c035-9371-578f-b799-fd2a14e9e40f","slug":"l-carnitine","display_name":"L-Carnitine","entity_type_key":"small_molecule"},"role":"excreted-metabolite","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"d7508505-8a1e-5bd1-9e23-05042800a967","slug":"guinea-pig-urinary-carnitine-excretion","display_name":"Guinea-pig urinary carnitine excretion","entity_type_key":"cellular_process"},"role":"readout","stoichiometry":null,"state_label":"","sequence_order":2,"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":"Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Guinea-pig dietary deficiency with pair feeding and precursor loading","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Vitamin C deficient diet for 28 days; oral trimethyllysine or gamma-butyrobetaine 0.5 mmol/kg/day on days 19–28, with replete and pair-fed controls.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Authors favored excessive excretion as an explanation for depletion; this does not isolate a renal transporter or quantify its contribution in human deficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin C research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-c","display_name":"Vitamin C","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Cavia porcellus","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Greater loss in urine can contribute to low carnitine during vitamin C deficiency.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[carnitine1995] The ability of guinea pigs to synthesize carnitine at a normal rate from epsilon-N-trimethyllysine or gamma-butyrobetaine in vivo is not compromised by experimental vitamin C deficiency. (1995). https://pubmed.ncbi.nlm.nih.gov/7752911/ DOI: 10.1016/0026-0495(95)90120-5","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Whole animal; urine-based synthesis estimate","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":"ae49358c-9934-5971-af75-c6c54350a2f9","evidence_kind":"source_excerpt","locator":"Lines 780-791","start_line":780,"end_line":791,"excerpt":"### vc-enzyme-deficient-carnitine-excretion\nWithout carnitine-precursor supplements, vitamin-C-deficient guinea pigs excreted approximately three times as much free and total carnitine as replete animals on days 19–28; pair feeding alone did not produce that pattern.\nCondition category: nutrient_deficiency\nnutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Greater loss in urine can contribute to low carnitine during vitamin C deficiency.\norganism: Cavia porcellus\ntissue_or_cell_type: Whole animal; urine-based synthesis estimate\nexperimental_model: Guinea-pig dietary deficiency with pair feeding and precursor loading\nlimitations: Authors favored excessive excretion as an explanation for depletion; this does not isolate a renal transporter or quantify its contribution in human deficiency.\ncross_nutrient: Vitamin C chemistry in collagen, modified-lysine/carnitine metabolism or copper-dependent peptide/catecholamine processing.\nexposure: Vitamin C deficient diet for 28 days; oral trimethyllysine or gamma-butyrobetaine 0.5 mmol/kg/day on days 19–28, with replete and pair-fed controls.\n[carnitine1995] The ability of guinea pigs to synthesize carnitine at a normal rate from epsilon-N-trimethyllysine or gamma-butyrobetaine in vivo is not compromised by experimental vitamin C deficiency. (1995). https://pubmed.ncbi.nlm.nih.gov/7752911/ DOI: 10.1016/0026-0495(95)90120-5","model_system":"Guinea-pig dietary deficiency with pair feeding and precursor loading","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [carnitine1995] The ability of guinea pigs to synthesize carnitine at a normal rate from epsilon-N-trimethyllysine or gamma-butyrobetaine in vivo is not compromised by experimental vitamin C deficiency. 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