Groscolas R, Leloup J
Gen Comp Endocrinol. 1986 Aug;63(2):264-74. doi: 10.1016/0016-6480(86)90164-4.
Changes in plasma thyroxine (T4) and triiodothyronine (T3) levels were studied during a breeding season and in more detail during the postbreeding molt in male and female emperor (Aptenodytes forsteri) and adelie (Pygoscelis adeliae) penguins under natural conditions in the Antarctic. During the 4-month natural fast that accompanies courtship and incubation in male emperors, plasma T4 and T3 levels were maintained around 11 and 0.6 ng/ml, respectively. In courting, fasting female emperors plasma T4 levels were maintained around 10 ng/ml for more than 1 month; plasma T3 levels were around 0.8 ng/ml but were markedly depressed (0.1 ng/ml) at the time of copulation although they increased again (2.2 ng/ml) at oviposition. During the 5-month period of chick rearing, plasma T3 (males and females) and T4 (females) were maintained at the same levels as during courtship and incubation, but plasma T4 levels in male emperors were slightly lower (7 ng/ml). Similar plasma T4 and T3 levels were observed in breeding adelie penguins. These results do not provide any convincing evidence for thyroid-gonadal interrelations in breeding penguins, but demonstrate their capacity to maintain plasma thyroid hormone levels during very prolonged natural fasts. During the heavy postnuptial molt when the birds were fasting, in both species and sexes, marked but separate peaks in plasma T4 and T3 levels occurred concurrently with the initial growth of the new feathers, and with the subsequent shedding of the old plumage, respectively. Peak plasma T4 levels were observed at the time of the emergence of the new feathers out of the skin, and peak plasma T3 levels were roughly concurrent with the maximum daily body weight loss. This is the first strong evidence that increases in plasma T4 and T3 levels are correlated with different stages of molt in a wild seabird. Increased plasma T4 but not T3 levels at the time of feather papilla eruption suggest that T4 is concerned with feather growth, but is not exclusive of a role of T3. Increased plasma T3 but not T4 levels during the reduction in thermal insulation in molting penguins suggest that this hormone rather than T4 might be active in energy metabolism in penguins.
在南极自然条件下，研究了雄性和雌性帝企鹅（阿德利企鹅属）和阿德利企鹅（阿德利企鹅属）在繁殖季节以及繁殖后换羽期间血浆甲状腺素（T4）和三碘甲状腺原氨酸（T3）水平的变化。在雄性帝企鹅求偶和孵化伴随的4个月自然禁食期间，血浆T4和T3水平分别维持在11和0.6 ng/ml左右。在求偶、禁食的雌性帝企鹅中，血浆T4水平在1个月以上的时间里维持在10 ng/ml左右；血浆T3水平约为0.8 ng/ml，但在交配时显著降低（0.1 ng/ml），不过在产卵时又再次升高（2.2 ng/ml）。在育雏的5个月期间，血浆T3（雄性和雌性）和T4（雌性）维持在与求偶和孵化期间相同的水平，但雄性帝企鹅的血浆T4水平略低（7 ng/ml）。在繁殖的阿德利企鹅中观察到了类似的血浆T4和T3水平。这些结果没有为繁殖企鹅的甲状腺 - 性腺相互关系提供任何令人信服的证据，但证明了它们在非常长时间的自然禁食期间维持血浆甲状腺激素水平的能力。在婚后剧烈换羽期间，当鸟类禁食时，在两个物种和性别中，血浆T4和T3水平的显著但分开的峰值分别与新羽毛的初始生长以及随后旧羽毛的脱落同时出现。在新羽毛从皮肤中长出时观察到血浆T4水平峰值，血浆T3水平峰值大致与每日最大体重减轻同时出现。这是第一个有力证据，表明血浆T4和T3水平的升高与野生海鸟换羽的不同阶段相关。在羽乳头出现时血浆T4水平升高但T3水平未升高，这表明T4与羽毛生长有关，但不排除T3的作用。在换羽企鹅隔热减少期间血浆T3水平升高但T4水平未升高，这表明这种激素而非T4可能在企鹅的能量代谢中起作用。
