Alpha- but not beta-adrenergic receptors mediate the effect of angiotensin II in the medial preoptic area on gonadotropin and prolactin secretion.
The aim of this work was to study the participation of alpha- and beta-adrenergic receptors on the effect of microinjection of angiotensin II (A II) into the medial preoptic area (MPOA) on the secretion of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) in estrogen-primed ovariectomized (OVX) rats. Microinjection of A II into the MPOA increased plasma LH. This effect was reduced by previous microinjection of an alpha- (phentolamine), but not a beta- (propranolol) adrenergic blocker into the MPOA. Plasma PRL decreased after microinjection of A II into the MPOA, but this effect was unchanged by phentolamine or propranolol. There was no change in plasma FSH in any condition. These results indicate that A II in the MPOA stimulates LH secretion and inhibits PRL secretion in estrogen-primed OVX rats. The effect on secretion of LH, but not of PRL, is mediated by alpha-adrenergic receptors in the MPOA.
Dornelles
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Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, SP, Brasil.
Franci
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CR
D000704:Analysis of Variance; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006065:Gonadotropins, Pituitary / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000378:metabolism; D008845:Microinjections; D011301:Preoptic Area / Q000187:drug effects*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D004967:Estrogens; D006065:Gonadotropins, Pituitary; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D000804:Angiotensin II; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone