Departamento de Morfologia, Instituto de Biologia, Universidade Federal de Pelotas, Campus Universitário s/n, Pelotas, Rio Grande do Sul, Caixa Postal 354, 96010-900, Brazil.
Vet J. 2011 Feb;187(2):255-9. doi: 10.1016/j.tvjl.2009.11.022. Epub 2009 Dec 30.
Serum levels of gonadal steroid hormones, corticosterone and thyroxin (T(4)), were monitored monthly in two male and one female captive Loggerhead sea turtles (Caretta caretta) over a period of 12 months in 2004 and 3 months in 2006. Ovary ultrasonography was performed in April and July 2006. The turtles were kept together in an outdoor sea pool in natural temperature and photoperiod conditions from May to November, then in separate indoor pools from December to April. Circulating hormone levels were measured by radioimmunoassay. Oestradiol levels in the female turtle surged significantly in July, as did the progesterone level in September. Total testosterone levels were different in both males, but both peaked in September. The peaks of oestradiol in the female and testosterone in the males did not coincide, both showing delay with respect to the hormone cycle described in free-ranging Loggerhead sea turtles. A seasonal pattern in T(4) levels was not observed. The three captive turtles showed very low corticosterone levels throughout the year, with a September peak coinciding with the peaks of progesterone in females and testosterone in males. The results suggested that conditions of captivity should be as close as possible to natural conditions throughout the entire year since the process of vitellogenesis in this species is protracted. Exposure to natural conditions for only a few months is insufficient to induce reproduction/oviposition.
2004 年，我们对两只雄性和一只雌性圈养的红海龟（Caretta caretta）进行了为期 12 个月，以及 2006 年 3 个月的每月一次的性腺类固醇激素、皮质酮和甲状腺素（T4）的血清水平监测。2006 年 4 月和 7 月进行了卵巢超声检查。5 月至 11 月期间，海龟被饲养在户外海水池中，处于自然温度和光照条件下，12 月至 4 月期间被饲养在单独的室内水池中。通过放射免疫分析法测量循环激素水平。7 月，雌性海龟的雌二醇水平显著上升，9 月孕激素水平也上升。两只雄性海龟的总睾酮水平不同，但均于 9 月达到峰值。雌性的雌二醇和雄性的睾酮峰值并不吻合，两者均显示出相对于自由放养红海龟的激素周期的延迟。未观察到 T4 水平的季节性模式。三只圈养海龟全年的皮质酮水平都非常低，9 月的峰值与雌性的孕激素和雄性的睾酮峰值相吻合。研究结果表明，由于该物种的卵黄发生过程漫长，因此全年的饲养条件应尽可能接近自然条件。仅接触自然条件几个月不足以诱导繁殖/产卵。
