Effects of human chorionic gonadotropin (hCG) and prolactin (PRL) on 3 beta-hydroxy-5-ene-steroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) expression and activity in the rat ovary.
Using a recently cloned rat ovary 3 beta-HSD cDNA and antibodies raised against purified human placental 3 beta-HSD, we have studied the effects of treatment with human chorionic gonadotropin (hCG) and hyperprolactinemia achieved by pituitary implants, alone or in combination, on the expression and activity of ovarian 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) in intact adult rats. 32P- and 35S-labeled cDNA probes were used to evaluate the effects of treatments on 3 beta-HSD mRNA levels by dot blot and in situ hybridization, respectively, while enzymatic activity was measured by the conversion of [14C]dehydroepiandrosterone into [14C]androstenedione. The present data show that hCG exerts a marked trophic effect on rat corpora lutea with an increase in total ovarian 3 beta-HSD mRNA levels, 3 beta-HSD protein content as well as enzymatic activity, resulting in an increase in serum progesterone levels. Prolactin-secreting pituitary implants alone, on the other hand, while exerting small effects on 3 beta-HSD expression and activity, led to a marked potentiation of the stimulatory effect of hCG on all parameters. The present data show that hCG and PRL act synergistically to stimulate ovarian progesterone secretion via an increase in 3 beta-HSD mRNA levels, protein content and enzymatic activity.
Martel
C
C
Medical Research Council Group in Molecular Endocrinology, CHUL Research Center, Québec, Canada.
Labrie
C
C
Couët
J
J
Dupont
E
E
Trudel
C
C
Luu-The
V
V
Takahashi
M
M
Pelletier
G
G
Labrie
F
F
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics* / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D015342:DNA Probes; D003687:Dehydroepiandrosterone / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D009693:Nucleic Acid Hybridization; D010053:Ovary / Q000187:drug effects / Q000201:enzymology*; D010902:Pituitary Gland / Q000378:metabolism / Q000637:transplantation; D011388:Prolactin / Q000097:blood / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D006063:Chorionic Gonadotropin; D015342:DNA Probes; D012333:RNA, Messenger; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D011388:Prolactin; D015096:3-Hydroxysteroid Dehydrogenases; C031954:delta(5)-3 beta-hydroxysteroid dehydrogenase