Non-aromatizing androgen 19-hydroxylase in human fetal organs

• Published in: Nippon Naibunpi Gakkai zasshi Vol. 65; no. 7; p. 653
• Main Authors: Shimizu, Y, Kosaki, T, Hashino, M, Sugisaki, K, Yanaihara, T, Nakayama, T, Osawa, Y
• Format: Journal Article
• Language: Japanese
• Published: Japan 20.07.1989
• Subjects: Adrenal Glands - embryology; Adrenal Glands - enzymology; Adrenal Glands - metabolism; Androstenedione - analogs & derivatives; Androstenedione - metabolism; Aromatase - metabolism; Estrogens - biosynthesis; Humans; Liver - embryology; Liver - enzymology; Liver - metabolism; Steroid Hydroxylases - metabolism
• ISSN: 0029-0661
• DOI: 10.1507/endocrine1927.65.7_653

19-hydroxyandrostenedione (19-OH A), known for many years as an obligatory intermediate of estrogen biosynthesis, has recently been found to be an amplifier of aldosterone action and in itself a hypertensinogenic steroid (J. Steroid Biochem., 16; 329, 1982). To search the presence of a non-aromatizing andorgen 19-hydroxylase in fetal organs, metabolism of labeled androstenedione(A) in fetal adrenal, liver, lung, brain and kidney was studied. 19-hydroxylase activity was calculated by the amounts of 19-OH A formed from A. The tissue homogenate was incubated with [4-14C]A and NADPH for different periods of time under air. The product, [4-14C] 19-OH A with added carrier standard [6,7-3H] 19-OH A was separated and purified by TLC, acetylation and TLC to constant 3H/14C ratio. The identity of the product was established by C.C.D. and by GC-MS analysis of purified product 19-AcOA in a larger scale adrenal incubation of non-labeled A. 19-hydroxylase activity was 0.9 pmol/min/mg protein for adrenal, but there was a negligible quantity of 19-OH A in lung, brain and kidney. Estrogen production was also assayed by 3H-water method using [1 beta-3H, 4-14C] A (3H/14C = 69.9). No detectable amount of estrogen was found in incubation of any homogenate except for liver. These results indicate that the non-aromatizing 19-hydroxylase activity in fetal adrenal gland is much higher than that in other organs. This is the first report to demonstrate the presence of 19-hydroxylase in human fetal adrenal tissue. It is suggested that 19-OH A secreted from fetal adrenal may also be associated with serum concentration of fetal circulation.