Milligan S R, Sarna G S
J Endocrinol. 1981 Jan;88(1):39-47. doi: 10.1677/joe.0.0880039.
Portacaval anastomosis (PCA) in the rat may be a useful experimental model for examining endocrine changes that occur during cirrhosis of the liver. A marked reduction in diet intake and body weight occurs in rats after establishing the shunt and studies were undertaken to determine the relationship of these effects to the testicular atrophy that also follows PCA. Control, sham-operated animals, experiencing a reduction in food intake similar to that of the animals with a PCA, showed reduced plasma levels of LH and testosterone but also exhibited a marked testicular response to LH. This was consistent with increased sensitivity of the hypothalamic-pituitary axis to the negative feedback of gonadal steroids in chronically underfed animals. Male rats with a PCA exhibited similarly reduced levels of LH and testosterone, but showed poor secretory responses of the pituitary gland to LH releasing hormone (LH-RH) and of the testis to LH. Testicular atrophy and cessation of spermatogenesis occurred in the animals with a PCA. These results suggested that the effects of PCA on the pituitary-gonadal axis cannot simply be explained as a consequence of the restricted intake of diet. This was confirmed by the responses to castration. In both fed and underfed sham-operated rats, castration resulted in a rapid and sustained increase in plasma LH and both groups showed a marked LH secretory response to LH-RH. In contrast, in animals with a PCA castration had little effect on plasma LH and the pituitary response to LH-RH was still poor. The effects of PCA cannot be simply explained by impeded metabolism of gonadal steroids causing increased negative feedback on the hypothalamic-pituitary axis.
大鼠门腔静脉吻合术（PCA）可能是一种用于研究肝硬化期间发生的内分泌变化的有用实验模型。建立分流术后，大鼠的饮食摄入量和体重显著下降，因此开展了研究以确定这些影响与PCA术后出现的睾丸萎缩之间的关系。假手术对照动物的食物摄入量下降程度与PCA动物相似，其血浆促黄体生成素（LH）和睾酮水平降低，但对LH仍表现出明显的睾丸反应。这与长期营养不足动物的下丘脑 - 垂体轴对性腺类固醇负反馈的敏感性增加一致。患有PCA的雄性大鼠的LH和睾酮水平同样降低，但垂体对促黄体生成素释放激素（LH - RH）的分泌反应以及睾丸对LH的反应较差。PCA动物出现了睾丸萎缩和精子发生停止。这些结果表明，PCA对垂体 - 性腺轴的影响不能简单地解释为饮食摄入受限的结果。去势反应证实了这一点。在喂食和未喂食的假手术大鼠中，去势导致血浆LH迅速且持续升高，两组对LH - RH均表现出明显的LH分泌反应。相比之下，在PCA动物中，去势对血浆LH几乎没有影响，垂体对LH - RH的反应仍然很差。PCA的影响不能简单地用性腺类固醇代谢受阻导致下丘脑 - 垂体轴负反馈增加来解释。
