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(2011). https://pubmed.ncbi.nlm.nih.gov/21918059/ DOI: 10.3945/jn.111.146126","model_system":"Leucine challenge during biotin depletion in two cohorts of 5 and 7 healthy adults","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b7-p21918059] Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans. 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