Tang K, Bartke A, Gardiner C S, Wagner T E, Yun J S
Department of Physiology, School of Medicine, Southern Illinois University, Carbondale.
J Androl. 1994 Jan-Feb;15(1):9-14.
To determine the effects of testosterone on the regulation of gonadotropins in metallothionein-1/human growth hormone (MT/hGH) transgenic mice, basal and gonadotropin-releasing hormone (GnRH)-stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release from incubated pituitaries, as well as pituitary content of LH, FSH, and mRNA for their respective beta subunits, were measured in normal and transgenic males that were injected with testosterone propionate (5 micrograms/g body weight; 24 hours before autopsy), injected with oil vehicle, castrated for 10 days, or sham operated. In normal (non-transgenic) males, exogenous testosterone induced the expected suppression, and castration induced the expected stimulation of various parameters of gonadotropin synthesis and release. In contrast, in testosterone-treated and in castrated MT/hGH transgenic mice the release of LH and the pituitary levels of LH-beta mRNA did not differ from the corresponding values measured in vehicle-injected and sham-operated transgenic controls. Pituitary LH content was elevated in testosterone-treated MT/hGH transgenic mice but was not changed in castrated transgenic males. The changes in pituitary levels of FSH and FSH-beta mRNA and in FSH release in MT/hGH transgenic mice in response to testosterone and castration were different from the changes in LH and LH-beta mRNA in the same mice, but similar to the changes of FSH and FSH-beta message produced in normal mice by identical treatments. We suggest that hGH expression attenuates the effects of testosterone on the mechanisms controlling LH release, with less influence on testosterone regulation of LH synthesis. These effects of hGH expression appear to be selective for LH, without influencing the FSH control system.
为了确定睾酮对金属硫蛋白-1/人生长激素（MT/hGH）转基因小鼠促性腺激素调节的影响，我们对正常和转基因雄性小鼠进行了如下处理：注射丙酸睾酮（5微克/克体重，尸检前24小时）、注射油赋形剂、阉割10天或假手术，然后测定孵育垂体中基础促性腺激素释放激素（GnRH）刺激的促黄体生成素（LH）和促卵泡生成素（FSH）释放情况，以及垂体中LH、FSH及其各自β亚基的mRNA含量。在正常（非转基因）雄性小鼠中，外源性睾酮诱导了预期的抑制作用，而阉割则诱导了促性腺激素合成和释放各项参数的预期刺激作用。相比之下，在接受睾酮处理和阉割的MT/hGH转基因小鼠中，LH的释放以及垂体中LH-β mRNA的水平与注射赋形剂和假手术的转基因对照小鼠所测的相应值没有差异。在接受睾酮处理的MT/hGH转基因小鼠中，垂体LH含量升高，但在阉割的转基因雄性小鼠中未发生变化。MT/hGH转基因小鼠垂体中FSH和FSH-β mRNA水平以及FSH释放对睾酮和阉割的反应与同一小鼠中LH和LH-β mRNA的变化不同，但与正常小鼠经相同处理后FSH和FSH-β信息的变化相似。我们认为hGH的表达减弱了睾酮对控制LH释放机制的影响，对睾酮调节LH合成的影响较小。hGH表达的这些影响似乎对LH具有选择性，而不影响FSH控制系统。
