Turner B B
Department of Physiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614.
Brain Res. 1992 May 29;581(2):229-36. doi: 10.1016/0006-8993(92)90712-i.
Binding parameters of soluble Type I and Type II receptors were assessed in hippocampus of adult, adrenalectomized, male and female rats. No sex differences in the number of either Type I or Type II receptors could be demonstrated between gonadally intact animals. When females treated with 17 beta-estradiol benzoate (10 micrograms/day) were compared with males, a statistically significant reduction in Type II receptors was observed in the females; progesterone produced no further decrease in receptor numbers. The amount of tissue-associated corticosteroid-binding globulin in gonadally intact animals (perfused with dextran-saline) was twice as great in females as males. Sex-dependent differences in these gonadally intact rats were found in the affinity, measured as the dissociation constant (Kd), of both the Type I and Type II receptors. For both receptors, affinity in cytosols from females was reduced. The difference for the Type II receptor was slight, but the Kd value of the Type I receptor was several-fold higher in females. The difference in affinity was evident with both natural and synthetic steroid ligands. There appears to be little, if any, difference in affinity between the hippocampal Type I and the Type II receptors in females. This suggests that the occupancy of Type I receptors in females is substantially less than that of males at low circulating concentrations of corticosteroids.
在成年、去肾上腺的雄性和雌性大鼠的海马体中评估了可溶性I型和II型受体的结合参数。在性腺完整的动物中，未发现I型或II型受体数量存在性别差异。当将用苯甲酸雌二醇（10微克/天）处理的雌性与雄性进行比较时，观察到雌性的II型受体有统计学上的显著减少；孕酮并未使受体数量进一步减少。性腺完整的动物（用葡聚糖盐水灌注）中组织相关皮质类固醇结合球蛋白的量在雌性中是雄性的两倍。在这些性腺完整的大鼠中，I型和II型受体的亲和力（以解离常数Kd衡量）存在性别依赖性差异。对于这两种受体，雌性细胞质中的亲和力均降低。II型受体的差异较小，但I型受体的Kd值在雌性中高出几倍。天然和合成类固醇配体的亲和力均存在明显差异。雌性海马体I型和II型受体之间的亲和力似乎几乎没有差异。这表明在皮质类固醇循环浓度较低时，雌性I型受体的占有率远低于雄性。
