Participation of ovarian 20 alpha-hydroxysteroid dehydrogenase in luteotrophic and luteolytic processes during rat pseudopregnancy.
In normal rats, before Day 12 of pseudopregnancy, minimal levels of 20 alpha-HSD activity were detected in functional CL whereas those in the residue were 3-5 times higher. When ovulation was blocked for more than 2 weeks by placing rats in a continuously lit environment before the induction of pseudopregnancy, only minimal levels of 20 alpha-HSD activity were detectable in the functional CL and residue before Day 12. In normal pseudopregnant rats, there was a linear increase in 20 alpha-HSD activity from Day 12 to 15 in the functional CL and residue, but the rate of elevation was much higher in functional CL. This tendency was much more clear-cut in rats in the continuous lighting. In immature rats in which pseudopregnancy was induced by PMSG and hCG treatment, 20 alpha-HSD activity peaked twice. The first small peak was attributed to the early regression of some of the large number of corpora lutea, and the changes in 20 alpha-HSD activity in most of the corpora lutea paralleled those in rats in continuous lighting. Bromocriptine abolished the prolactin surges, and in normal pseudopregnant rats an increase in 20 alpha-HSD activity in functional CL started from 12 h and the rate of the increase was accelerated from 36 h afterwards, while a relatively small increase was observed in the residue at 18 h and later.(ABSTRACT TRUNCATED AT 250 WORDS)
Matsuda
J
J
Department of Veterinary Physiology, Faculty of Agriculture, University of Tokyo, Japan.
Noda
K
K
Shiota
K
K
Takahashi
M
M
D004092:20-alpha-Dihydroprogesterone / Q000097:blood; D000818:Animals; D003338:Corpus Luteum / Q000201:enzymology; D003340:Corpus Luteum Maintenance / Q000502:physiology*; D003600:Cytosol / Q000201:enzymology; D005260:Female; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D003341:Luteolysis / Q000502:physiology*; D010053:Ovary / Q000201:enzymology; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011555:Pseudopregnancy / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains
D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone; D006913:Hydroxysteroid Dehydrogenases; C019189:12 alpha-hydroxysteroid dehydrogenase