Lormée H, Jouventin P, Chastel O, Mauget R
Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, Villiers en bois, 79360, France.
Horm Behav. 1999 Feb;35(1):9-17. doi: 10.1006/hbeh.1998.1491.
Plasma levels of luteinizing hormone (LH) and prolactin associated with parental behavior were measured in the Antarctic winter breeding emperor penguin, Aptenodytes forsteri. Males exclusively incubate the egg while females exclusively brood the nonhomeothermic young; both sexes alternate in rearing the homeothermic young. Birds were sampled on arrival from the sea through egg laying, incubation, and brooding. All parent birds lost their chicks at the end of the brooding period due to harsh weather but sampling continued. In females, LH titers dropped after egg laying but levels were restored when the birds returned from the sea to brood the chicks and were not depressed by high prolactin levels. Plasma prolactin remained low in males captured on arrival and kept until the free-living males finished incubation. In breeders, prolactin secretion increased during the prelaying period when day length decreased. Prolactin levels stayed elevated in males during incubation and in brooding females returning after a 2-month absence at sea. Prolactin values were higher in brooding females than in males ending incubation or returning in late brooding. These levels did not drop after chick loss, and the sexual difference in prolactin values was maintained after breeding failure. In emperor penguins, increased prolactin secretion appears to be triggered around the time of egg laying and continues, driven by an endogenous mechanism, through incubation and brooding until rearing is completed. Prolactin secretion independent of external stimuli may have evolved in pelagic seabirds to maintain parental care despite long absences at sea from the breeding colony.
在南极冬季繁殖的帝企鹅（Aptenodytes forsteri）中，测量了与亲代行为相关的促黄体生成素（LH）和催乳素的血浆水平。雄性专门孵蛋，而雌性专门照料体温不恒定的幼雏；两性交替抚养体温恒定的幼雏。从鸟类从海上归来开始，经过产卵、孵蛋和育雏阶段进行采样。由于恶劣天气，所有亲鸟在育雏期结束时都失去了幼雏，但采样仍继续进行。在雌性中，产卵后LH滴度下降，但当鸟类从海上返回育雏时水平恢复，且不受高催乳素水平的抑制。刚捕获时雄性的血浆催乳素水平较低，并一直保持到自由生活的雄性完成孵蛋。在繁殖期的鸟类中，当白昼长度减小时，产卵前催乳素分泌增加。雄性在孵蛋期间以及在海上离开两个月后返回育雏的雌性中，催乳素水平持续升高。育雏雌性的催乳素值高于结束孵蛋或在育雏后期返回的雄性。幼雏丢失后这些水平并未下降，繁殖失败后催乳素值的性别差异仍然存在。在帝企鹅中，催乳素分泌增加似乎在产卵时触发，并通过一种内源性机制持续作用，贯穿孵蛋和育雏阶段直至抚养完成。在远洋海鸟中，可能已经进化出独立于外部刺激的催乳素分泌，以便在与繁殖群体长期分离于海上期间维持亲代抚育行为。
