Beta-endorphin inhibition of progesterone secretion by porcine granulosa cells during follicle development.
Exogenous beta-endorphin or the opioid antagonist, naloxone, was added to the culture medium of control or LH-treated granulosa cells to elucidate the role of beta-endorphin in follicular steroidogenesis. beta-endorphin decreased basal progesterone (P4) production by Gc isolated from small and medium follicles and had no effect on P4 production by cells from large follicles. beta-endorphin decreased P4 production by LH-treated Gc isolated from small, medium and large follicles. Naloxone increased basal P4 production by cells from small and medium follicles and had no effect on P4 production by Gc from large follicles. Neither agent had any effect on basal oestradiol (E2) secretion by Gc from any of the follicles. However, E2 secretion by LH-treated Gc from all sizes of follicles was inhibited by beta-endorphin, with the greatest effect on cells from small follicles. We conclude that opioid peptides act in the follicle in a paracrine manner to prevent excessive basal progesterone secretion by Gc and may also be involved in the regulation of LH action on granulosa cells steroidogenesis during follicle development.
Department of Animal Physiology, Institute of Zoology, Jagiellonian University, Cracow, Poland. greg@zuk.iz.uy.edu.pl
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Gregoraszczuk
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Słomczyńska
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects* / Q000502:physiology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology*; D011374:Progesterone / Q000096:biosynthesis / Q000378:metabolism*; D013552:Swine / Q000502:physiology*; D001615:beta-Endorphin / Q000008:administration & dosage / Q000494:pharmacology*
D009292:Narcotic Antagonists; D009270:Naloxone; D011374:Progesterone; D004958:Estradiol; D001615:beta-Endorphin; D007986:Luteinizing Hormone