Yeung W S, Chan S T
Gen Comp Endocrinol. 1987 Jun;66(3):353-63. doi: 10.1016/0016-6480(87)90244-9.
By Celite chromatography and radioimmunoassay, the levels of free and conjugated forms of androstenedione, testosterone, 11-oxotestosterone, 11 beta-hydroxytestosterone, 17 beta-estradiol, and estrone have been determined in the plasma of the protandrous sex-reversing Rhabdosargus sarba at different sexual phases throughout the seasonal reproductive cycle. Free androstenedione showed a significant increase during the spawning period in the functional male phase, while a prespawning increase in both the free and the conjugated androstenedione was found in the female phase. The level of testosterone remained fairly constant throughout the reproductive cycle in all sexual phases except the intersexual phase, which was found to have a slight increase in the free testosterone level during the spawning period. Females showed a prespawning increase in free 17 beta-estradiol and conjugated estrone; the former dropped while the latter remained unchanged in the succeeding spawning period. A prespawning rise of conjugated 17 beta-estradiol was also found in the male specimens. The level of free estrone was undetectable in the plasma of Rhabdosargus. No variation in the levels of 11-oxotestosterone and 11 beta-hydroxytestosterone was found in the different sexual phases throughout the reproductive cycle. The present study showed that in general the steroid patterns in the male and intersexual phases were basically similar, except perhaps that the levels of conjugated 17 beta-estradiol, conjugated androstenedione, and free testosterone were slightly higher in the intersex than in the male during the spawning period. The changes in the plasma levels of sex steroids were correlated with the structural transformation in the gonad and the seasonal cycle of the fish. The results were analyzed with special references to the phenomenon of natural sex reversal and to the endocrine patterns known in other teleost fishes.
通过硅藻土色谱法和放射免疫分析法，测定了在季节性繁殖周期中处于不同性相的雄性先熟性逆转的平鲷血浆中雄烯二酮、睾酮、11-氧代睾酮、11β-羟基睾酮、17β-雌二醇和雌酮的游离形式和结合形式的水平。游离雄烯二酮在功能性雄性阶段的产卵期显著增加，而在雌性阶段，游离和结合雄烯二酮在产卵前均增加。除了雌雄同体阶段，在所有性相的整个繁殖周期中，睾酮水平保持相当恒定，雌雄同体阶段在产卵期游离睾酮水平略有增加。雌性在产卵前游离17β-雌二醇和结合雌酮增加；前者在随后的产卵期下降，而后者保持不变。在雄性标本中也发现结合17β-雌二醇在产卵前升高。在平鲷血浆中未检测到游离雌酮水平。在整个繁殖周期的不同性相中，未发现11-氧代睾酮和11β-羟基睾酮水平有变化。本研究表明，一般来说，雄性和雌雄同体阶段的类固醇模式基本相似，只是在产卵期，雌雄同体中结合17β-雌二醇、结合雄烯二酮和游离睾酮的水平可能比雄性略高。性类固醇血浆水平的变化与性腺的结构转变和鱼类的季节性周期相关。结合自然性逆转现象和其他硬骨鱼类已知的内分泌模式对结果进行了分析。
