Effect of the rat estrous cycle at ovariectomy on striatal D-1 dopamine receptors.
We have investigated the effect of the surgical suppression of gonadal steroid hormones by ovariectomy on striatal D-1 dopamine (DA) receptors, in relation with the stage of the estrous cycle at the time of surgery. Plasma levels of 17 beta-estradiol and progesterone declined rapidly to a minimum one and two days after ovariectomy, respectively. Ovariectomy of female rats in proestrus led to an increased density of striatal D-1 DA from the first to the fourth day following surgery with a return to control values on the 7th day. Rats ovariectomized (OVX) in estrus showed an increased striatal D-1 DA receptor density from the second to the fourth day following surgery with a return to control values 7 days following ovariectomy. Striatal D-1 DA receptor density of rats OVX in diestrus remained constant up to 7 days after surgery. The affinity of striatal D-1 DA receptors remained unchanged in all cases. Therefore, this report illustrates that steroid hormonal fluctuations as occurring during the 4-day estrous cycle of the rat can modulate striatal D-1 DA receptors.
Lévesque
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School of Pharmacy, Laval University, Québec, Canada.
Di Paolo
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D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism* / Q000502:physiology; D004971:Estrus; D005260:Female; D010052:Ovariectomy; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D017447:Receptors, Dopamine D1
D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1