Rasmussen L E, Hess D L, Luer C A
Department of Biochemistry and Molecular Biology, Oregon Graduate Institute of Science and Technology, Portland, Oregon 97291-1000, USA.
J Exp Zool. 1999 Oct 1;284(5):575-85. doi: 10.1002/(sici)1097-010x(19991001)284:5<575::aid-jez13>3.3.co;2-9.
Serum steroid hormones in the peripheral circulation of the clearnose skate, Raja eglanteria, were measured at the time of capture and at various times throughout the year while the animals were maintained as a captive breeding population. These analyses demonstrate interesting correlations between changes in hormone concentrations and annual reproductive events. Animals were sampled once (78 females, 20 males) or multiple times (15 females). For both groups of females, 17beta-estradiol was detected throughout the year with significant elevations occurring during October and November when ovarian follicles begin to mature (as determined through necropsy examinations), and January and February when maximum mating activity is observed and egg laying begins. Testosterone and dihydrotestosterone concentrations were significantly elevated in females only during January and February. Testosterone elevations were synchronous with longer-term elevations in 17beta-estradiol in females sampled either once or repetitively. Testosterone concentrations in males were significantly elevated during times of maximum breeding activity compared to periods of sexual inactivity. Data from females sampled during five stages of the egg laying process, as defined by the position of palpable egg capsules within the reproductive tract, revealed that 17beta-estradiol was highest when egg capsules were forming in the nidamental gland (stage 2) or uterus (stage 3); testosterone and dihydrotestosterone were maximal when eggs were in the uterus (stage 3) or cloaca (stage 4); and progesterone was significantly elevated immediately after oviposition (stage 5), suggesting a possible role for progesterone in the regulation of sequential laying of egg pairs. J. Exp. Zool. 284:575-585, 1999.
在捕获时以及全年的不同时间，对圈养繁殖群体中的星点鳐（Raja eglanteria）外周循环中的血清类固醇激素进行了测量。这些分析表明激素浓度变化与年度繁殖事件之间存在有趣的相关性。动物被采样一次（78只雌性，20只雄性）或多次（15只雌性）。对于两组雌性，全年都检测到17β-雌二醇，在10月和11月卵巢卵泡开始成熟时（通过尸检确定）以及1月和2月观察到最大交配活动并开始产卵时，其浓度显著升高。睾酮和双氢睾酮浓度仅在1月和2月的雌性中显著升高。在单次或重复采样的雌性中，睾酮升高与17β-雌二醇的长期升高同步。与性不活跃期相比，雄性在最大繁殖活动期的睾酮浓度显著升高。根据生殖道内可触及的卵囊位置定义的产卵过程五个阶段对雌性进行采样的数据显示，当卵囊在缠卵腺（第2阶段）或子宫（第3阶段）形成时，17β-雌二醇最高；当卵在子宫（第3阶段）或泄殖腔（第4阶段）时，睾酮和双氢睾酮最高；排卵后（第5阶段）孕酮显著升高，表明孕酮可能在调节成对产卵的顺序中起作用。《实验动物学杂志》284:575 - 585，1999年。
