[Steroid secretion from ovaries with delayed ovulation in rats (author's transl)].
The present study was carried out to determine if alterations in steroid-producing ability of ovary could account for the abnormal embryonic development which follows delayed ovulation. The rats treated for 1 or 2 days with Nembutal were used as the animal model with delay of ovulation. In normal rats before the ovulation, the ovaries secreted predominantly estradiol-17 beta (E2) and later, after the ovulation, produced mainly progesterone (P) and 5 alpha-dihydroprogesterone (5 alpha-DHP). In rats that failed to ovulate, the levels of E2 remained high on the first day of blockade and decreased to very low levels on the second day of blockade, while P and 5 alpha-DHP remained at low levels during this period. After the ovulation which follows delayed ovulation, there was still a shift in the steroid secretory patterns, which was similar to that observed in the normal ovaries. However, the concentrations of 5 alpha-DHP was significantly lower than that after normal ovulation. The injection of LH greatly increased the secretion of 5 alpha-DHP within 30 min in both the normal and the blocked ovaries, but the steroid-producing ability of ovaries which follows delayed ovulation was low, suggesting low 5 alpha-reductase in the ovary with delayed ovulation. It is said that physiologic effect of 5 alpha-DHP is concerned in life of blastocysts. These results suggest that the abnormal embryonic development which follows delayed ovulation may be causally related to the low 5 alpha-reductase activity in the blocked ovaries.
D004092:20-alpha-Dihydroprogesterone / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D005317:Fetal Growth Retardation / Q000209:etiology; D010049:Ovarian Diseases / Q000378:metabolism; D010053:Ovary / Q000201:enzymology / Q000378:metabolism*; D010060:Ovulation; D010088:Oxidoreductases / Q000378:metabolism; D011247:Pregnancy; D011374:Progesterone / Q000031:analogs & derivatives* / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone; D004958:Estradiol; D010088:Oxidoreductases; C022447:3-oxo-5-alpha-steroid 4-dehydrogenase (NADP(+))