Manning N J, Kime D E
Gen Comp Endocrinol. 1985 Mar;57(3):377-82. doi: 10.1016/0016-6480(85)90217-5.
The effect of temperature on steroidogenesis in the male rainbow trout has been studied both in vitro using endogenous precursors under gonadotrophin stimulation and in vivo in fish held for 2 weeks at three different temperatures. In vitro, the optimum temperature for formation of testosterone and its 11-oxygenated derivatives was 10 degrees, whereas glucuronide formation showed an optimum at 18 degrees. In vivo, plasma levels of testosterone and 11-keto-testosterone were significantly higher at 6 than at 17 degrees, whereas glucuronide levels showed no significant difference. Milt was obtained only from fish held at 6 and 12 degrees. The optimum temperature for free steroid formation in response to gonadotrophin stimulus is shown to be dependent upon glucuronyl transferase content, and its progressive increase during the reproductive cycle may provide a mechanism for the inhibition of free steroid synthesis and hence spermiation at elevated temperatures where gamete survival is poor.
一是在促性腺激素刺激下，使用内源性前体在体外进行研究；二是在体内，将鱼置于三种不同温度下饲养2周进行研究。在体外，睾酮及其11-氧化衍生物形成的最适温度为10℃，而葡糖醛酸苷形成的最适温度为18℃。在体内，6℃时睾酮和11-酮睾酮的血浆水平显著高于17℃时，而葡糖醛酸苷水平无显著差异。仅从饲养在6℃和12℃的鱼中获得了精液。结果表明，响应促性腺激素刺激的游离类固醇形成的最适温度取决于葡糖醛酸基转移酶的含量，并且在生殖周期中其含量的逐渐增加可能提供一种机制，用于抑制游离类固醇的合成，从而在配子存活率较低的高温下抑制排精。
