Proudman J A, Wentworth B C
Germplasm and Gamete Physiology Laboratory, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA.
Domest Anim Endocrinol. 1996 May;13(3):277-82. doi: 10.1016/0739-7240(96)00018-5.
Incubation behavior in the turkey hen is associated with a large increase in prolactin secretion. Previous research using hourly sampling of incubating hens has shown that prolactin levels fluctuate widely throughout a 24-hr period, suggestive of pulsatile secretion. This study compared the prolactin secretory patterns of laying and incubating turkeys to determine if prolactin is secreted episodically and if the high prolactin levels characteristic of the incubating hen may result, at least in part, from a change in the amplitude or frequency of secretory pulses. Blood samples were collected from cannulated, unrestrained laying and incubating hens at 10-min intervals for up to 24 hr. Data were analyzed with the PULSAR program to determine baseline prolactin levels and to establish the magnitude, frequency, and duration of episodic secretory peaks. The results revealed tha prolactin is secreted in a pulsatile pattern in both laying and incubating turkey hens. Incubating hens had ninefold higher mean and baseline plasma prolactin levels than laying hens. The prolactin pulses were of approximately 12-fold greater amplitude in incubating hens than in laying hens, but the duration and frequency of pulses were the same in both groups. Therefore, the high prolactin levels required for incubation do not appear to result from an increase in the frequency of lactotroph stimulation, but rather from an increase in the prolactin secretion rate.
母火鸡的孵卵行为与催乳素分泌大幅增加有关。此前对正在孵卵的母火鸡进行每小时一次采样的研究表明，催乳素水平在24小时内波动很大，提示有脉冲式分泌。本研究比较了产蛋期和孵卵期火鸡的催乳素分泌模式，以确定催乳素是否呈间歇性分泌，以及孵卵母火鸡特有的高催乳素水平是否至少部分是由分泌脉冲的幅度或频率变化所致。从通过插管处理且未受限制的产蛋母火鸡和孵卵母火鸡采集血样，每隔10分钟采集一次，持续24小时。使用PULSAR程序分析数据，以确定催乳素的基础水平，并确定间歇性分泌峰值的大小、频率和持续时间。结果显示，产蛋期和孵卵期的母火鸡催乳素均以脉冲模式分泌。孵卵母火鸡的平均血浆催乳素水平和基础血浆催乳素水平比产蛋母火鸡高九倍。孵卵母火鸡的催乳素脉冲幅度比产蛋母火鸡大12倍左右，但两组脉冲的持续时间和频率相同。因此，孵卵所需的高催乳素水平似乎并非由促乳细胞刺激频率增加所致，而是由催乳素分泌速率增加所致。
