Caldwell J D, Walker C H, Pedersen C A, Mason G A
Dept. of Psychiatry, School of Medicine, University of North Carolina, Chapel Hill 27599.
Life Sci. 1993;52(22):1781-6. doi: 10.1016/0024-3205(93)90467-h.
Sexual interactions have multiple effects on oxytocin systems in the brain. In the present study we observed that allowing estrogen-progesterone treated ovariectomized rats to be mounted ten times by a male significantly decreased the density (beta max) of thymic oxytocin receptors. Animals were ovariectomized and after recovery injected once daily for three consecutive days with 0.5 microgram estradiol benzoate (EB) followed by an injection of 500 micrograms progesterone on the fourth day 4-5 hr before testing. They were either placed in a cage with a sexually-active male until mounted ten times (mounted) or were briefly placed in the cage and removed before being mounted (unmounted). Both groups were then killed and their thymuses aseptically removed. Computerized analysis of saturation binding data showed that the densities of oxytocin receptors from mounted animals were significantly (p < 0.02) lower than those of unmounted controls (beta max for unmounted animals = 8.45 +/- 0.84 fmol/mg protein; and for mounted rats = 5.5 +/- 0.33 fmol/mg protein; t6 = 3.23). The possibility is discussed that sexual activity reduces thymic oxytocin receptors which may alter immune responsiveness to sexually-transmitted diseases.
性互动对大脑中的催产素系统有多种影响。在本研究中，我们观察到，让接受雌激素 - 孕酮处理的去卵巢大鼠被雄性交配十次，会显著降低胸腺催产素受体的密度（最大结合量）。将动物进行去卵巢手术，恢复后连续三天每天注射一次0.5微克苯甲酸雌二醇（EB），并在测试前4 - 5小时的第四天注射500微克孕酮。它们要么被放入与有性活性的雄性共处的笼子里，直到被交配十次（已交配组），要么短暂放入笼子后在被交配前取出（未交配组）。然后处死两组动物，并无菌取出它们的胸腺。对饱和结合数据的计算机分析表明，已交配动物的催产素受体密度显著低于未交配的对照组（p < 0.02）（未交配动物的最大结合量 = 8.45 ± 0.84 fmol/mg蛋白质；已交配大鼠的最大结合量 = 5.5 ± 0.33 fmol/mg蛋白质；t6 = 3.23）。本文讨论了性活动降低胸腺催产素受体这一可能性，而这可能会改变对性传播疾病的免疫反应。
