These experiments were performed to analyze whether treatments of ovariectomized female rats with ovarian steroid regimens able to induce either an increase (positive feedback effect) or a decrease (negative feedback effect) of serum levels of luteinizing hormone (LH) have some impact on the characteristics of mu-opioid binding sites in circumscribed areas of the brain. The increase of serum levels of LH elicited by a treatment with estradiol benzoate (EB) plus progesterone (P; positive feedback effect) was accompanied by a significant decrease in the number of mu-binding sites in the hypothalamus and in the corpus striatum. The decrease in serum levels of LH induced by a treatment with EB alone (negative feedback effect) brought about a significant increase of the number of mu-binding sites in the thalamus and in the hippocampus. These results seem to suggest that the release of LH induced by EB plus P may involve a decrease of hypothalamic mu-binding sites. Apparently, the inhibitory effect on LH release exerted by EB alone does not involve any change of the density of these binding sites in the hypothalamus.

Effects of ovarian hormones on brain opioid binding sites in castrated female rats / D. Dondi, P. Limonta, R. Maggi, F. Piva. - In: AMERICAN JOURNAL OF PHYSIOLOGY. - ISSN 0002-9513. - 263:3 Pt 1(1992 Sep), pp. E507-E511.

Effects of ovarian hormones on brain opioid binding sites in castrated female rats

D. Dondi
Primo
;
P. Limonta
Secondo
;
R. Maggi
Penultimo
;
F. Piva
Ultimo
1992-09

Abstract

These experiments were performed to analyze whether treatments of ovariectomized female rats with ovarian steroid regimens able to induce either an increase (positive feedback effect) or a decrease (negative feedback effect) of serum levels of luteinizing hormone (LH) have some impact on the characteristics of mu-opioid binding sites in circumscribed areas of the brain. The increase of serum levels of LH elicited by a treatment with estradiol benzoate (EB) plus progesterone (P; positive feedback effect) was accompanied by a significant decrease in the number of mu-binding sites in the hypothalamus and in the corpus striatum. The decrease in serum levels of LH induced by a treatment with EB alone (negative feedback effect) brought about a significant increase of the number of mu-binding sites in the thalamus and in the hippocampus. These results seem to suggest that the release of LH induced by EB plus P may involve a decrease of hypothalamic mu-binding sites. Apparently, the inhibitory effect on LH release exerted by EB alone does not involve any change of the density of these binding sites in the hypothalamus.
μ-opioid binding sites; corpus striatum; estradiol; hippocampus; hypothalamus; luteinizing hormone; negative feedback effect of estradiol; positive feedback effect of estradiol plus progesterone; progesterone; thalamus
Settore BIO/13 - Biologia Applicata
Settore BIO/09 - Fisiologia
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/181939
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