Goldsmith A R, Nicholls T J
Gen Comp Endocrinol. 1984 May;54(2):247-55. doi: 10.1016/0016-6480(84)90178-3.
Using radioimmunoassays, prolactin, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured in the plasma of intact, castrated, and testosterone-implanted male starlings. Two groups of birds (intact and castrated males) were transferred when photosensitive from short (8-hr) to long (16-hr) day lengths; in both cases plasma prolactin levels increased steadily reaching a peak after 5 weeks of photostimulation, at the time of the onset of photorefractoriness . Three groups ( intacts , castrates, and castrates implanted with Silastic capsules containing testosterone) were exposed to day lengths increasing by 30 min per week from 8 to 16 hr. Again, prolactin levels increased in a similar fashion in all three groups at the time of refractoriness, which occurred when the day length reached 15-16 hr. Thus the timing of photorefractoriness and the associated rise in prolactin secretion which occur in response to photostimulation do not depend upon the presence of the gonads and are not affected when testosterone is maintained at a constant high level. Nor is the increase in prolactin altered when the cycle of gonadotrophin secretion which normally precedes it is completely suppressed by the implantation of a testosterone capsule. It would seem that prolactin secretion in the starling is stimulated by transfer from short to long day lengths, but not as a consequence of high gonadotrophin or androgen secretion rates.
利用放射免疫分析法，对完整、阉割和植入睾酮的雄性椋鸟血浆中的催乳素、促黄体生成素（LH）和促卵泡生成素（FSH）进行了测定。两组鸟（完整雄性和阉割雄性）在光敏期从短日照（8小时）转移到长日照（16小时）；在这两种情况下，血浆催乳素水平稳步上升，在光刺激5周后达到峰值，此时正是光不应期开始的时候。三组（完整组、阉割组和植入含睾酮硅橡胶胶囊的阉割组）暴露于每周增加30分钟的日照时长下，从8小时增加到16小时。同样，在光不应期时，所有三组的催乳素水平以相似的方式升高，当日照时长达到15 - 16小时时出现光不应期。因此，对光刺激产生的光不应期的时间以及与之相关的催乳素分泌增加并不依赖于性腺的存在，并且当睾酮维持在恒定的高水平时也不受影响。当正常先于催乳素分泌的促性腺激素分泌周期被植入睾酮胶囊完全抑制时，催乳素的增加也不会改变。看来，椋鸟催乳素的分泌是由从短日照到长日照的转变刺激的，而不是高促性腺激素或雄激素分泌率的结果。
