Comparison of Metabolites of Progesterone-4-14C in Urine from a Nonpregnant Domestic Sow

Urine excreted following intravenous administration of 9 µc. representing 166 mcg. of progesterone-4-14C to one sow on day 13 and day 19 of the estrous cycle was used to evaluate extraction procedures and to characterize the steroid compounds containing 14C. Approximately 80% of the radioactivity in urine was rendered extractable by sequential treatment with β-glucuronidase enzyme and solvolysis. An additional 17% was extracted after treatment of the latter aqueous residue with acid which indicates the presence of conjugates other than simple glucuronides or sulfates. A major portion of the extracted radioactivity was in the neutral fraction (89%) as compared with 6.6% in the acid+phenolic and 4.3% in the petroleum ether-benzene phenolic fractions. Four major metabolites of progesterone-4-14C, previously identified, account for 80 to 90% of the radioactivity in the neutral fraction. Four other unidentified 14C metabolites were isolated but these represent only a small portion of the metabolites of progesterone in sow urine.