Ovarian steroidogenic enzyme activities during the rat estrous cycle.
We have correlated the concentrations of serum LH, estradiol and progesterone with the activities of 2 ovarian steroid biosynthetic enzymes during the rat estrous cycle. Ovarian 3 beta-hydroxysteroid dehydrogenase isomerase (3-beta HSD) activity decreased from 29 +/- 6 nmol/mg protein/min (mean +/- SEM) in diestrus, to 7 +/- 0.4 nmol/mg protein/min in late proestrus (p less than 0.005), and subsequently increased to 36 +/- 9 nmol/mg protein/min in metestrus (p less than 0.01). Ovarian 17-hydroxylase (17-OH) activity decreased from early to late proestrus (3.3 +/- 0.2 vs 2.2 +/- 0.2 nmol/mg protein/min, p less than 0.0025), and subsequently increased to 3.9 +/- 0.2 in metestrus (p less than 0.001). Serum LH, estradiol and progesterone peaked during proestrus, and reached a nadir during estrus. We conclude that the activities of 3-beta HSD and 17-OH in the rat ovary vary markedly during the estrous cycle. These changes may underlie the pattern of steroid secretion characteristic of this process.
D000818:Animals; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D008861:Microsomes / Q000378:metabolism; D010053:Ovary / Q000201:enzymology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D013256:Steroids / Q000096:biosynthesis*
D012739:Gonadal Steroid Hormones; D013256:Steroids; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone