Proudman J A
Avian Physiology Laboratory, Agricultural Research Service, USDA, Beltsville, Maryland 20705.
Domest Anim Endocrinol. 1991 Apr;8(2):265-70. doi: 10.1016/0739-7240(91)90062-o.
Plasma concentrations of prolactin and corticosterone were determined in hourly samples collected over a 25-hr period from unrestrained turkey hens exhibiting incubation (broody) behavior. Hens were maintained in cages on a 14 hr light: 10 hr dark photoperiod. Mean plasma prolactin concentration increased significantly late in the dark period to reach maximum daily levels of 496 ng/ml at the start of the photophase. However, a well-defined daily rhythm in prolactin secretion was not evident. Plasma corticosterone concentration showed a significant daily rhythm characterized by a major secretory peak (7.14 ng/ml) in the middle of the light period and a smaller, less well-defined peak (4.11 ng/ml) during the dark period. Both prolactin and corticosterone secretion ranged widely throughout the day in individual hens in a manner suggestive of pulsatile hormone secretion. This study demonstrates that the extremely high prolactin concentrations characteristic of the incubating turkey hen reflect large, dynamic changes in plasma prolactin concentrations occurring throughout the photoperiod, rather than a constantly high level of prolactin secretion.
在25小时内，从表现出抱窝（孵卵）行为的自由活动火鸡母鸡身上每小时采集样本，测定血浆中催乳素和皮质酮的浓度。母鸡饲养在笼子里，光照周期为14小时光照：10小时黑暗。血浆催乳素平均浓度在黑暗期后期显著增加，在光照期开始时达到每日最高水平496纳克/毫升。然而，催乳素分泌的明确每日节律并不明显。血浆皮质酮浓度呈现出显著的每日节律，其特征是在光照期中期出现一个主要分泌峰值（7.14纳克/毫升），在黑暗期出现一个较小且不太明确的峰值（4.11纳克/毫升）。在个体母鸡中，催乳素和皮质酮的分泌在一天中都有很大的波动，提示激素分泌呈脉冲式。这项研究表明，抱窝火鸡母鸡特有的极高催乳素浓度反映了整个光照周期内血浆催乳素浓度的巨大动态变化，而不是催乳素分泌持续处于高水平。
