Biosynthetic pathways for corticoids and androgen formation in human fetal adrenal tissue in vitro.

Eleven incubations of minced human fetal adrenal tissue from two fetuses at midtrimester of pregnancy terminated for socio-economic reasons, were performed for different periods of time with labelled pregnenolone, progesterone, 17alpha-hydroxyprogesterone and deoxycorticosterone (DOC). The order of magnitudes of enzyme activity when progesterone was used as a substrate and incubated with midterm fetal adrenals was 17alpha-hydroxylase, 21-hydroxylase and 16alpha-hydroxylase. The activity of 3beta-hydroxysteroid dehydrogenase and delta5-4 isomerase was almost negligible as compared to other enzymic activities as mentioned above. Similar biosynthetic pathways for adrenal corticoids formation were observed in human fetal adrenals as reported in human adults and animals; once progesterone was converted into DOC, further 17alpha-hydroxylation did not take place.