Yamamoto Yuki, Yamamoto Tatsuya, Watanabe Gen, Yuto Natsuki, Keio Megumi, Narushima Etsuo, Katayanagi Masayuki, Nakao Risa, Morikubo Syu, Sakurai Yuko, Kaneko Mikako, Kaewmanee Saroch, Taya Kazuyoshi
Department of Basic Veterinary Science, Gifu University, Gifu, Japan.
J Vet Med Sci. 2010 Jul;72(7):845-52. doi: 10.1292/jvms.09-0480. Epub 2010 Feb 24.
Reproduction of captive elephants in zoos has shown a low fecundity and requires improvement. One of the reasons for low fecundity is ovarian dysfunction in many female elephants. To investigate whether prolactin has a correlation with ovarian function in female elephants, the serum concentrations of prolactin, progesterone and estradiol-17beta in four African female elephants (one cycling female and three non-cycling female elephants) were measured. Cyclic patterns of prolactin and estradiol-17beta were observed in the cycling female elephant, which tended to be high during the follicular phase and low during the luteal phase. On the other hand, a cyclic pattern of prolactin was not observed in the non-cycling female elephants. One of the three non-cycling females (Mako) had developed breasts and showed significantly higher average levels of prolactin than the other female elephants. These results suggested that high concentrations of circulating estradiol-17beta during the follicular phase stimulated prolactin secretion. They also suggested that hyperprolactinemia in Mako was one of the causes of the developed mammary glands and ovarian dysfunction.
动物园中圈养大象的繁殖率较低，需要改善。繁殖率低的原因之一是许多雌象存在卵巢功能障碍。为了研究催乳素与雌象卵巢功能是否相关，测定了4头非洲雌象（1头处于发情周期的雌象和3头非发情周期的雌象）血清中催乳素、孕酮和雌二醇-17β的浓度。在处于发情周期的雌象中观察到催乳素和雌二醇-17β的周期性变化，在卵泡期往往较高，而在黄体期较低。另一方面，在非发情周期的雌象中未观察到催乳素的周期性变化。3头非发情周期的雌象之一（真子）乳房发育，其催乳素平均水平明显高于其他雌象。这些结果表明，卵泡期循环中高浓度的雌二醇-17β刺激了催乳素的分泌。研究结果还表明，真子的高催乳素血症是乳腺发育和卵巢功能障碍的原因之一。
