Effect of beta-endorphin on cAMP and progesterone accumulation in rat luteal cells.
The aim of this study is to investigate the effect of beta-endorphin on cAMP and progesterone accumulation in rat luteal cells. Luteal cells of 4-day-old corpora lutea were cultured for 3 h in the absence or presence of 0.001 or 0.01 IU/ml hCG, and cAMP, progesterone and beta-endorphin levels in the medium were measured by RIA. hCG stimulated the production of cAMP, progesterone and beta-endorphin. In the presence of hCG, treatment with islet-activating protein (IAP) led to overall augmentation of cAMP and progesterone accumulation in comparison with untreated controls. In the absence or presence of low doses of hCG (0.001 IU/ml), beta-endorphin did not affect progesterone production, but inhibited cAMP accumulation. This inhibitory effect was abolished by pre-treatment with IAP. In the presence of high doses of hCG (0.01 IU/ml), however, beta-endorphin stimulated progesterone production without a corresponding increase in cAMP. This stimulatory effect was also abolished by IAP-treatment. These results suggest that luteal cells produce and release beta-endorphin that affects cAMP and progesterone production via IAP-sensitive mechanisms.
Kato
T
T
Department of Endocrinology, Medical Research Institute, Tokyo Medical and Dental University, Japan.
Kumai
A
A
Okamoto
R
R
D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D003338:Corpus Luteum / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism*; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D037342:Pertussis Toxin; D011374:Progesterone / Q000032:analysis / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D010566:Virulence Factors, Bordetella; D001615:beta-Endorphin / Q000378:metabolism / Q000494:pharmacology*
D006063:Chorionic Gonadotropin; D010566:Virulence Factors, Bordetella; D011374:Progesterone; D001615:beta-Endorphin; D000242:Cyclic AMP; D037342:Pertussis Toxin