Hernández M L, Fernández-Ruiz J J, de Miguel R, Ramos J A
Department of Biochemistry, Faculty of Medicine, Complutense University, Madrid, Spain.
J Neural Transm Gen Sect. 1991;83(1-2):77-84. doi: 10.1007/BF01244454.
In this work, we have studied the time-course of the effects of pharmacological administration of ovarian steroids on tyrosine hydroxylase (TH) activity in the limbic forebrain of ovariectomized rats. Administration of estradiol produced a late decrease in TH activity. This effect was found 24 hours after the last steroid injection, disappearing at 32 hours. It was antagonized by progesterone, since a single injection of this steroid to estradiol-pretreated rats reversed to control values the estradiol-induced decrease. Nevertheless, the administration of progesterone after estradiol treatment caused a short-time decrease in the limbic activity of TH, which was observed 4 hours after the last steroid injection, disappearing subsequently. On the other hand, the administration of progesterone alone produced a biphasic effect, with a reduction at 24 hours, followed by an increase at 32 hours. These effects were only observed in the animals non-treated with estradiol, disappearing with a previous treatment with estrogens. Hence, it can be concluded that both ovarian steroids may affect the limbic TH activity. Thus, estradiol produced a late inhibitory effect on the activity of this enzyme, which was antagonized by progesterone. Administration of the last one to estradiol-treated rats produced a short-time inhibitory effect, whereas its administration to non-treated rats produced a late biphasic effect (inhibition followed by stimulation), which was not observed in estradiol-treated rats.
在这项研究中，我们研究了给去卵巢大鼠边缘前脑药理注射卵巢甾体激素对酪氨酸羟化酶（TH）活性影响的时间进程。注射雌二醇会导致TH活性出现后期下降。这种效应在最后一次甾体激素注射后24小时出现，32小时时消失。它可被孕酮拮抗，因为对预先用雌二醇处理过的大鼠单次注射这种甾体激素可使雌二醇诱导的下降逆转至对照值。然而，在雌二醇处理后注射孕酮会导致边缘前脑TH活性出现短期下降，这在最后一次甾体激素注射后4小时观察到，随后消失。另一方面，单独注射孕酮会产生双相效应，24小时时降低，随后在32小时时升高。这些效应仅在未用雌二醇处理的动物中观察到，在用雌激素预先处理后消失。因此，可以得出结论，两种卵巢甾体激素都可能影响边缘前脑的TH活性。因此，雌二醇对该酶的活性产生后期抑制作用，该作用可被孕酮拮抗。给用雌二醇处理过的大鼠注射孕酮会产生短期抑制作用，而给未处理的大鼠注射则会产生后期双相效应（先抑制后刺激），在用雌二醇处理的大鼠中未观察到这种效应。
