Human chorionic gonadotropin affects tissue levels of progesterone and cyclic adenosine 3',5'-monophosphate in the metestrus rat uterus in vitro.
The effect of human chorionic gonadotropin (hCG) on in vitro progesterone (P) level in the uterus was investigated by using short-term incubations of uterine tissue taken from 4-day cyclic rats at different stages of the estrous cycle. Control incubations resulted in a decrease of endogenous P content in uteri removed from rats in proestrus (PRO), estrus (EST), and metestrus (MET): -25% (n = 6), -60% (n = 6), and -45% (n = 8), respectively. The amount of P found after incubation of MET tissue in the presence of hCG was significantly higher (p less than 0.001) than that found after control incubations. The hCG effect was dose-dependent and was not observed with PRO or EST tissue. Although the mean P level found in MET tissue after incubation with 10 IU/ml hCG was not significantly different from the mean level found in unincubated tissue (1562 +/- 341 vs. 1470 +/- 174 pg/mg protein, n = 8), an obvious synthesis was observed in two experiments. It thus seems likely that observed hCG effect would involve a de novo P synthesis rather than a decrease of P catabolism. Furthermore, hCG induced a dose-dependent increase of cyclic adenosine 3', 5'-monophosphate (cAMP) uterine levels in MET tissue. N,O'-dibutyryl cyclic AMP [Bu)2 cAMP) at 5 mM induced a significative increase (p less than 0.01) of P uterine level in EST and MET tissue compared to control incubations, but had no effect on PRO tissue. Our results suggest the progressive maturation throughout the rat estrous cycle of a luteinizing hormone/hCG- and cAMP-dependent process able to regulate uterine P content.(ABSTRACT TRUNCATED AT 250 WORDS)
Bonnamy
P J
PJ
Laboratoire de Biochimie, C.N.R.S. U.A. 609, C.H.U. Cote de Nacre, Caen, France.
Benhaim
A
A
Leymarie
P
P
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D004971:Estrus / Q000187:drug effects*; D005260:Female; D007986:Luteinizing Hormone / Q000378:metabolism; D008686:Metestrus / Q000187:drug effects*; D011374:Progesterone / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
D006063:Chorionic Gonadotropin; D011374:Progesterone; D003994:Bucladesine; D007986:Luteinizing Hormone; D000242:Cyclic AMP