METABOLISM OF NEUTRAL STEROIDS IN HUMAN FETUS .I. DISTRIBUTION OF RADIOACTIVE MATERIAL IN PREVIABLE HUMAN FETUS AFTER ADMINISTRATION OF PROGESTERONE-4-14C

Progesterone-4-14C was injected into three male fetuses after 13 to 22 weeks gestation via the pulsating umbilical vein within a period of 30 seconds. The first fetus was examined 8 minutes after the injection, the second 12 minutes, and the third 18 minutes after the injection. Much radioactivity present in the free form amounted to 85.1%, 78.6% and 73.1% of the total, respectively. Other tissues of the fetuses, such as the kidney and adrenal, were also examined and the results obtained confirm those of other workers. The radioactivity in the liver was analyzed and the following metabolites were isolated and identified: 20α-dihydroprogesterone (49.0%, 30.6% and 35.5% of the total free steroid, respectively); 17α-hydroxyprogesterone (1.6% 1.5% and 1.5%, respectively); 16α-hydroxyprogesterone (1.8% of the radioactivity in the fetus after 13 weeks gestation); and 5β-pregnane-3α,5α-diol (2.4% in the fetus after 17 weeks, and 2.4% in the fetus after 22 weeks gestation). © 1968.