Silverin B, Goldsmith A
Gen Comp Endocrinol. 1984 Aug;55(2):239-44. doi: 10.1016/0016-6480(84)90107-2.
Plasma prolactin concentrations in female pied flycatchers are high during incubation, but fall from 156 +/- 27 to 67 +/- 6 ng/ml (P less than 0.01) between 2 and 4 days after the young hatch. The timing of the fall in prolactin could be determined by factors associated with the hatching of the eggs and growth of the offspring; alternatively, prolactin may remain high for a fixed period (16 days) after the onset of incubation. To distinguish between these possibilities, eggs were exchanged between nest boxes to ensure incubation periods of either 10, 14, or 19 days by different females. The results showed that the period of high prolactin secretion was shortened by 2-4 days where the eggs hatched early, but, conversely, was not lengthened in those females with extended incubation periods, the levels actually falling in these birds before the eggs hatched. There was, however, a secondary rise in prolactin 3 days after hatching, when the level of 114 +/- 11 ng/ml 22 days after the onset of incubation was much higher than that (30 +/- 4 ng/ml) at a comparable stage in the control females. Thus, high prolactin secretion cannot be maintained for longer than 16-17 days in incubating birds, but newly hatched, naked young can stimulate prolactin release in female flycatchers over a flexible period.
雌性斑姬鹟在孵卵期间血浆催乳素浓度较高，但在雏鸟孵化后2至4天内，该浓度从156±27降至67±6纳克/毫升（P<0.01）。催乳素下降的时间可能由与卵孵化和后代生长相关的因素决定；或者，催乳素可能在开始孵卵后的固定时期（16天）内保持较高水平。为了区分这些可能性，在巢箱之间交换卵，以确保不同雌性的孵卵期分别为10天、14天或19天。结果表明，在卵提前孵化的情况下，催乳素高分泌期缩短了2至4天，但相反，在孵卵期延长的雌性中，该分泌期并未延长，实际上这些鸟的催乳素水平在卵孵化前就下降了。然而，在孵化后3天催乳素出现了二次升高，孵卵开始22天后催乳素水平为114±11纳克/毫升，远高于对照雌性在可比阶段的水平（30±4纳克/毫升）。因此，在孵卵的鸟类中，高催乳素分泌无法维持超过16至17天，但新孵化的、无毛的雏鸟可在一段灵活的时期内刺激雌性斑姬鹟释放催乳素。
