Schwabl H
Rockefeller University Field Research Center for Ecology and Ethology, Millbrook, NY 12545.
Proc Natl Acad Sci U S A. 1993 Dec 15;90(24):11446-50. doi: 10.1073/pnas.90.24.11446.
The sex steroid hormones that affect development in birds have been thought to be produced exclusively by the embryo or neonate. I used radioimmunoassay to measure the amounts of androstenedione, 5 alpha-dihydrotestosterone, testosterone, 17 beta-estradiol, and corticosterone in the yolk of freshly laid canary (Serinus canaria) and zebra finch (Poephila guttata) eggs. Testosterone was found in both canary and zebra finch eggs, but its contents were much higher in the former than in the latter. The testosterone content of canary eggs in a same clutch increased with the order of laying, regardless of the genetic sex of the offspring that hatched from these eggs. Yolk testosterone was also present in the eggs of female canaries that were kept without a male, indicating that it is of maternal origin. The social rank of juvenile canaries was positively correlated with the concentration of yolk testosterone in the eggs from which they hatched, suggesting that the development of aggressive behavior of offspring might be subject to modification by maternal testosterone. These findings indicate that female songbirds can bestow upon their eggs a dose of hormone that modifies the behavior of offspring. Variable doses of these hormones might explain some of the individual variation in offspring behavior.
影响鸟类发育的性类固醇激素一直被认为完全由胚胎或幼雏产生。我使用放射免疫分析法测量了刚产下的金丝雀（Serinus canaria）和斑胸草雀（Poephila guttata）卵黄中雄烯二酮、5α-二氢睾酮、睾酮、17β-雌二醇和皮质酮的含量。在金丝雀和斑胸草雀的卵中都发现了睾酮，但其含量在前者中比在后者中高得多。同一窝金丝雀卵中的睾酮含量随着产卵顺序的增加而增加，无论从这些卵中孵化出的后代的遗传性别如何。在没有雄性陪伴的雌性金丝雀所产的卵中也存在卵黄睾酮，这表明它来自母体。幼年金丝雀的社会等级与它们孵化自的卵中的卵黄睾酮浓度呈正相关，这表明后代攻击性行为的发育可能会受到母体睾酮的影响。这些发现表明，雌性鸣禽可以给它们的卵注入一定剂量的激素，从而改变后代的行为。这些激素剂量的变化可能解释了后代行为中的一些个体差异。
