This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'Metabolite of progesterone in urine \nSelect and explain. \nA. Pregnenolone, B. 17 hydroxypregnenolone, C. Pregnanediol, D. Pregnanetriol', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Metabolites of progesterone may be classified into 3 groups based on degree of reduction. Pregnanediones: the C4-5 double bond is reduced producing 2 pregnanediones and allopregnanediones Pregnanolones: the keto group at C3 is reduced producing a hydroxyl groups in alpha and beta orientation. Urinary pregnanolones exit in alpha orientation Pregnanediols: keto group at c20 is reduced and compounds with c20 hydroxyl groups in alpha orientation are quantitatively more impoant. Hence urinary measurement of pregnanediols can be used as an index of endogenous production of progesterone and also its concentration correlates well with many clinical conditions Ref: Katzung 12 th ed.', 'role': 'assistant'}]