性腺甾体激素对雌、雄大鼠下丘脑血管升压素mRNA水平的影响

EFFECTS OF GONADAL STEROID HORMONES ON HYPOTHALAMIC VASOPRESSIN mRNA LEVEL IN MALE AND FEMALE RATS

实验用１０－１１周龄经阉割的雌、雄Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠进行。以３′末端异羟基洋地黄毒甙标记的２６个碱基长的寡核苷酸作为检测探针，用核酸斑点杂交技术检测大鼠下丘脑血管升压素（ｖａｓｏｐｒｅｓｓｉｎ，ＡＶＰ）ｍＲＮＡ水平。在假手术对照组，雄性大鼠下丘脑ＡＶＰｍＲＮＡ水平比雌性大鼠高４５％（Ｐ＜０．０５），血浆渗透压高于雌性大鼠（Ｐ＜０．０５）。摘除卵巢的大鼠下丘脑ＡＶＰｍＲＮＡ水平比假手术组雌性大鼠高３０％（Ｐ＜０．０５）。摘除睾丸的大鼠下丘脑ＡＶＰｍＲＮＡ水平低于假手术组雄性大鼠，但其差别尚无统计学显著意义。阉割的雌、雄大鼠血浆渗透压无显著性差别。在阉割的雄性大鼠中，皮下注射雌二醇可降低下丘脑ＡＶＰｍＲＮＡ水平（Ｐ＜０．０５），而给予睾丸酮、孕酮及雌二醇与孕酮的混合物则没有作用。给摘除卵巢的雌性大鼠皮下注射雌二醇或雌二醇与孕酮的混合物都可使下丘脑ＡＶＰｍＲＮＡ水平下降（Ｐ＜０．０１），而注射睾丸酮或单独给予孕酮都没有作用。皮下注射各类性激素后，血浆渗透压与对照组无显著差别。这些结果提示，性腺甾体激素可影响大鼠下丘脑内ＡＶＰｍＲＮＡ的水平。

Experiments were carried out in 10-11-week old gonadectomized male and female Sprague-Dawley rats. Dot-blot analysis and 31-end digoxigenin-labeled 26 meroligonucleotide probe was used in detecting the mRNA level hypothalamic vasopressin(AVP). The basal hypothalamic AVP-mRNA level in the sham-operated intact maleswas 45% higher than that in the sham-operated intact females (P<0. 05). Plasma osmolality was also higher in the sham-operated intact males than in the sham-operated intact females (P<0. 05). The hypothalamic AVP-mRNA level in ovariectomized ratswas 30% higher than that in sham-operated intact females (P<0. 05). Although thehypothalamic AVP mRNA level tended to be lower in castrated males than in sham-operated intact males, the difference was not statistically significant. The difference inplasma osmolality between gonadectomized males and females was statistically insignificant. In castrated males, hypothalamic AVP-mRNA level was decreased following sc injection of estradiol (P< 0. 05), but testosterone, progesterone or a combination ofestradiol and progesterone were without effect. In ovariectomized rats, sc injection ofestradiol or a combination of estradiol and progesterone resulted in a decrease in hypothalamic AVP-mRNA level (P<0.01), but progesterone or testosterone had no effeet. The difference in plasma osmolality between gonadal steriod hormones-treated ratsand vehicle-treated rats was not statistically significant. These findings indicate that gonadal steriod hormones can affect hypothalamic AVP-mRNA level in rats, throughsome central mechanism.