Department of Zoology, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh, India.
Gen Comp Endocrinol. 2013 Jan 15;181:139-45. doi: 10.1016/j.ygcen.2012.11.004. Epub 2012 Nov 19.
Many hormones are known for their role in the regulation of metabolic activities and somatic growth in fishes. The present study deals with the effects of malathion (an organophosphorous pesticide) on the levels of metabolic hormones that are responsible for promotion of somatic and ovarian growth of the freshwater catfish, Clarias batrachus. Malathion treatment for thirty days drastically reduced the food intake and body weight of fish. These fish also exhibited a great avoidance to food. Exposure of catfish to malathion reduced the levels of thyroxine (T(4)), triiodothyronine (T(3)), growth hormone (GH), insulin like growth factor-I (IGF-I), testosterone (T) and estradiol-17β (E(2)) in a dose dependent manner during all the studied reproductive phases, in general, except that malathion increased the level of GH during the quiescence phase. Significant reduction in muscle and hepatic protein content also occurred in the malathion-treated fish. Malathion exposure induced lipolysis too in the liver and muscle. The results thus support that malathion treatment disrupts the endocrine functions and the olfactory sensation responsible for food intake and gustatory feeding behavior, which ultimately leads to retardation of fish growth.
许多激素因其在调节鱼类代谢活动和躯体生长中的作用而为人所知。本研究探讨了马拉硫磷（一种有机磷农药）对代谢激素水平的影响，这些激素负责促进淡水鲶鱼（Clarias batrachus）的躯体和卵巢生长。马拉硫磷处理 30 天可大大降低鱼类的食物摄入量和体重。这些鱼也表现出对食物的强烈回避。鲶鱼暴露于马拉硫磷中，在所有研究的生殖阶段，除了在静止期，马拉硫磷会增加生长激素（GH）的水平，总体上以剂量依赖的方式降低甲状腺素（T4）、三碘甲状腺原氨酸（T3）、生长激素（GH）、胰岛素样生长因子-I（IGF-I）、睾丸激素（T）和雌二醇-17β（E2）的水平。肌肉和肝蛋白质含量也在马拉硫磷处理的鱼中显著降低。马拉硫磷暴露也诱导肝脏和肌肉中的脂肪分解。结果表明，马拉硫磷处理会破坏负责食物摄入和味觉摄食行为的内分泌功能和嗅觉感觉，最终导致鱼类生长迟缓。
