大脑性分化前外源雄激素对雌鼠性定向影响的研究

Effect of exogenous androgen before sexual differentiation on sexual orientation in adult female rats

目的探讨雌鼠大脑性分化前性激素与性定向的关系并建立雌鼠同性恋模型。方法40只新生SpragueDawley雌鼠随机分4组,每组10只。第1,2,3组雌鼠在出生第1天分别腹腔注射丙酸睾酮(TP)25g·L-1·rat-1(低剂量TP组),50g·L-1·rat-1(中剂量TP组),100g·L-1·rat-1(高剂量TP组),第4组雌鼠注射无菌油(50μl/rat)作为雌鼠对照组。另外对10只新生雄鼠注射无菌油(50μl/rat)作为雄鼠对照组。成年后观察TP组雌鼠的性偏爱、雌性行为及雄性行为的变化。结果(1)中剂量TP组和高剂量TP组雌鼠的接近雌刺激鼠的时间长于雌鼠对照组(P<005,P<005),且高剂量TP组在雄刺激鼠和雌刺激鼠方面,更偏向于接近雌刺激鼠(Z=2521,P<005);(2)中剂量和高剂量TP组雌鼠的雌性行为明显减少于雌鼠对照组(P<005,P<005);(3)高剂量TP组的雄性行为明显增加,且与雄鼠对照组相的差异无统计学意义(P>005);(4)低剂量TP组雌鼠的性偏爱、雌性行为及雄性行为与雌鼠对照组的差异均无统计学意义(均P>005)。结论雌鼠大脑性分化前给予外源雄激素能影响其性偏爱及性行为。

Objective To study the influence of sex hormones before sexual differentiation on sexual orientation of female rats and establish a female rat homosexual model.Methods Forty postnatal Sprague-Dawley female rats (1 day old) were randomly distributed into four groups and each group were intraperitoneally injected different dosage of testosterone propionate (TP): 50 μl (2.5, 5.0, 10.0 g ·L~^-1 ·rat^-1 ), 0 (vehicle, 50 μl aseptic oil), and ten postnatal male rats (1 day old) were injected 50 μl aseptic oil as male controls, then sexual preference, feminine and masculine sexual behavior of the adults were observed.Results (1) Mid-dose group (TP 5.0 g·L~^-1 ·rat^-1 ) and high-dose group (TP 10.0 g·L~^-1 ·rat^-1 ) of female rats spent more time on the vicinity of female rats than the controls (P<0.05, ~P<0.05), and high-dose group spent significantly more time on the vicinity of female rat than the male rat (Z=2.521, P<0.05). (2) Mid-dose group and high-dose group had a significant reduction in the feminine sexual behavior compared to the female controls (P<0.05, P<0.05). (3) High-dose group displayed more masculine sexual behavior than the female controls, and had no difference with male controls (P>0.05). (4) Low-dose group (TP 2.5 g ·L~^-1 ·rat^-1 ) showed no difference in sexual preference, feminine and masculine sexual behavior compared with female controls (P>0.05, P>0.05, P>0.05).Conclusion Before sexual differentiation, exogenous androgen could have effect on the sexual preference and sexual behavior of female rat.