Yadav A K, Singh T P
Environ Res. 1986 Feb;39(1):136-42. doi: 10.1016/s0013-9351(86)80015-9.
The effects of malathion (an organophosphorus) and BHC (an organochlorine) exposure on circulating levels of plasma T3 and T4 were studied in the freshwater catfish, Heteropneustes fossilis. A lowered plasma T4 level was noticed within 4 weeks of malathion (10 and 20 ppm) and BHC (8 ppm) exposure. Higher concentrations of BHC (16 ppm) induced an increase in the plasma T4 level. BHC-exposed fish exhibited significantly lowered plasma T3 and T3/T4 ratio, but malathion exposure significantly increased their levels. Probably BHC acted directly on the thyroid gland, reducing the synthesis and release of the thyroid hormone. Malathion seems to increase the plasma T3 level either by stimulating the extrathyroidal conversion of T4 to T3 or by reducing T3 excretion, thereby increasing plasma T3 and the T3/T4 ratio in this fish.
研究了在淡水鲶鱼（印度胡鲶）中，马拉硫磷（一种有机磷）和六六六（一种有机氯）暴露对血浆中T3和T4循环水平的影响。在暴露于马拉硫磷（10 ppm和20 ppm）和六六六（8 ppm）4周内，发现血浆T4水平降低。较高浓度的六六六（16 ppm）导致血浆T4水平升高。暴露于六六六的鱼血浆T3和T3/T4比值显著降低，但暴露于马拉硫磷会使其水平显著升高。六六六可能直接作用于甲状腺，减少甲状腺激素的合成和释放。马拉硫磷似乎通过刺激T4向T3的外周转化或减少T3排泄来增加血浆T3水平，从而提高这种鱼的血浆T3和T3/T4比值。
