Abstract
Liver, adrenal, kidney, spleen, lung and brain samples (1.0g or 0.5g) from human fetuses (5 months, 6 months and 7 months) were sliced and incubated for 90 mins. with pregnenolone-3H. 16α-Hydroxypregnenolone formed was tentatively identified, since it had a constant specific radioactivity on repeated chromatographies. Per cent conversions of pregnenolone to 16α-hydroxypregnenolone were 36.8% to 13.7% for liver slices, 0.96% to 0.57% for adrenal slices, and less than 0.05% for kidney, spleen, lung and brain slices. Urinary excretion of 16α-hydroxypregnenolone was much greater than pregnenediol and pregnenolone in newborn boys but adrenal concentration of 16α-hydroxypregnenolone was much less than pregnenolone in autopsied newborns. From the data, it seems that pregnenolone synthesized by the fetal adrenal is hydroxylated at 16α-position mainly in the liver and partly in the adrenal.
