Effect of gonadal steroids on hypothalamus and anterior pituitary endo-oligopeptidase B (proline-endopeptidase) activity in castrated female rats.
In the present study we investigated the possible participation of endo-oligopeptidase B (poline-endopeptidase) in the control of gonadotrophin secretion through the control of LH-RH inactivation. This enzyme selectively hydrolyzes the Pro9-Gly10-NH2 peptide bond of LH-RH, thereby inactivating this substance. The enzyme activity was evaluated using a specific colorimetric substrate, i.e., Z-Gly-Pro-SM. Female adult Wistar rats were submitted to castration, experimental situations that are known to produce changes in gonadotrophin secretion. Hypothalamic and pituitary endo-oligopeptidase B activity was shown to be present predominantly in the soluble fraction of the enzyme preparations. The results also indicated that endo-oligopeptidase B activity adult female rat pituitary decreased after castration and increased after administration of estradiol and progesterone to castrated animals. The present results lead us to suggest that anterior pituitary endo-oligopeptidase B may be related to the control gonadotrophin secretion in female rats.
D000818:Animals; D002369:Castration; D010450:Endopeptidases / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000201:enzymology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000201:enzymology*; D011374:Progesterone / Q000494:pharmacology*; D000085822:Prolyl Oligopeptidases; D051381:Rats; D011919:Rats, Inbred Strains; D012697:Serine Endopeptidases
D011374:Progesterone; D004958:Estradiol; D010450:Endopeptidases; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases