Ovarian opioids and the reproductive cycle of the frog Rana esculenta.

摘要: Abstract In mammals, proopiomelanocortin-related peptides are involved in reproductive processes both at the hypothalamo-pituitary and ovarian levels. Using immunocytochemical, biochemical physiological “in vitro” studies, we provid here evidence for a diffuse POMC-related opioid system frog Rana esculenta . Ovarian β-endorphin (β-EP) is expressed thecal cells changes during cycle an inverse relationship with follicular development. Seasonal ovary different to those brain or pituitary. The ratio of acetylated vs native β-EP also over period, affecting biological activity peptide. During spring period summer post-reproductive phase pMol amounts stimulate androgen secretion vitro, naloxone-reversible way. either inhibition estradiol, possibly mediated via other factors, result action. conclusion, these data demonstrate first time widespread presence β-EP-related Both immunocytochemical evidence, as well vitro responses, support role seasonality this amphibian.