Clarke R N, Ottinger M A
Department of Poultry Science, University of Maryland, College Park 20742.
Biol Reprod. 1987 Oct;37(3):556-63. doi: 10.1095/biolreprod37.3.556.
The responsiveness of the anterior pituitary to exogenous luteinizing hormone-releasing hormone (LHRH; 20 micrograms/kg body weight) and the subsequent stimulation of testosterone secretion by the testes was studied after administration of dietary aflatoxin (10 ppm) to 9-wk-old male chickens. In both control and aflatoxin-treated males, there were significant (p less than 0.05) increases in plasma luteinizing hormone (LH) concentrations following LHRH administration, which peaked at 5 min post injection and declined thereafter. Plasma testosterone levels increased soon after the LHRH injection in control males, secondary to elevated LH levels in the peripheral circulation, and continued to increase throughout the experimental period. In contrast, this LH-induced elevation in plasma testosterone was delayed in aflatoxin-treated males, with no substantial increase until 20 min post-LHRH injection. In a subsequent experiment, castration of aflatoxin-fed males resulted in an altered response to exogenous LHRH, as compared to their intact counterparts. Based on these data, it appeared that while the LH-secretory capacity of the anterior pituitary was not diminished in birds receiving aflatoxin, the testicular response to exogenous LHRH was altered during aflatoxicosis. Additionally, the effect of castration on plasma LH profiles after LHRH administration provides preliminary evidence for extra-testicular effects of dietary aflatoxin on reproduction in the avian male.
在给9周龄雄性鸡投喂膳食黄曲霉毒素（10 ppm）后，研究了垂体前叶对外源性促黄体生成激素释放激素（LHRH；20微克/千克体重）的反应以及随后睾丸对睾酮分泌的刺激作用。在对照和黄曲霉毒素处理的雄性鸡中，注射LHRH后血浆促黄体生成激素（LH）浓度均显著（p<0.05）升高，在注射后5分钟达到峰值，随后下降。在对照雄性鸡中，LHRH注射后血浆睾酮水平很快升高，这是由于外周循环中LH水平升高所致，并在整个实验期间持续升高。相比之下，在黄曲霉毒素处理的雄性鸡中，LH诱导的血浆睾酮升高延迟，直到LHRH注射后20分钟才出现实质性升高。在随后的实验中，与完整的对照鸡相比，投喂黄曲霉毒素的雄性鸡阉割后对外源性LHRH的反应发生了改变。基于这些数据，似乎在接受黄曲霉毒素的鸡中，垂体前叶的LH分泌能力并未降低，但在黄曲霉毒素中毒期间，睾丸对外源性LHRH的反应发生了改变。此外，阉割对LHRH注射后血浆LH谱的影响为膳食黄曲霉毒素对雄性禽类生殖的睾丸外效应提供了初步证据。
