Changes in enzyme activities related to steroidogenesis in human ovaries during the menstrual cycle

The Journal of Clinical Endocrinology and Metabolism
Y SanoB Tamaoki

Abstract

Follicles and corpora lutea were isolated from the ovaries of 25 patients at several stages of the normal menstrual cycle. To measure the steroidogenic enzyme activities, cell-free homogenates of the ovaries were incubated aerobically with 4-14C-labeled pregnenolone, progesterone, 17 alpha-hydroxyprogesterone, androstenedione, and testosterone in the presence of appropriate cofactor(s). The delta 5-3 beta-hydroxysteroid dehydrogenase plus delta 4-delta 5 isomerase activity in the follicle was low during early follicular phase (greater than 11 days before ovulation), but gradually increased toward ovulation and showed maximal values in the corpus luteum at the midluteal phase (6-10 days after ovulation). The activities of 17 alpha-hydroxylase and C-17-C-20 lyase in the follicle reached the highest value at the late follicular phase (within 5 days of ovulation), but markedly decreased after luteinization. 17 alpha-Hydroxylase activity in the corpus luteum increased again during the midluteal phase, whereas the activity of C-17-C-20 lyase remained at a low level throughout the luteal phase. The aromatase activity was low during the follicular phase, but increased markedly with luteinization. These findings are discussed in light o...Continue Reading

Citations

Jan 1, 1987·Journal of Steroid Biochemistry·G S DiZeregaG Westhof
Feb 1, 1991·The Journal of Steroid Biochemistry and Molecular Biology·C Bijault, L Dehennin
Nov 14, 2002·The Journal of Steroid Biochemistry and Molecular Biology·F Alex FeltusMichael H Melner
Jan 2, 2010·The Journal of Steroid Biochemistry and Molecular Biology·Amanda C SwartPieter Swart
Nov 26, 2010·Molecular and Cellular Endocrinology·Karl-Heinz StorbeckAmanda C Swart
Feb 1, 1997·Endocrine Reviews·B C Fauser, A M Van Heusden
May 17, 2007·Gynecological Endocrinology : the Official Journal of the International Society of Gynecological Endocrinology·Christian De GeyterMaria De Geyter

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