Ravault J P, Martinet L, Bonnefond C, Claustrat B, Brun J
J Pineal Res. 1986;3(4):365-73. doi: 10.1111/j.1600-079x.1986.tb00758.x.
Removal of the superior cervical ganglia suppresses the inhibitory role of short days in prolactin secretion and luteal activity in pregnant or pseudopregnant mink. Alternatively, timed injections of melatonin replicate the inhibitory role of short days in females maintained under long days. To understand if the diurnal variation of melatonin secretion is part of the mechanism by which the mink measure day length, diurnal variations in plasma melatonin concentrations have been measured in intact and ganglionectomized females maintained under long or short days after mating. Melatonin was measured by radioimmunoassay according to Brun et al. [Adv. Biosci. 53:41-45]. In intact females, plasma concentrations ranged from nondetectable levels to 40 pg/ml during the day, increased shortly after the onset of the dark phase, and reached peak values during the middle of the night. The duration of the elevated levels was roughly proportional to the length of the night. No diurnal variations could be detected in ganglionectomized females; melatonin levels never exceeded the day values observed in intact females.
切除颈上神经节会抑制短日照对妊娠或假孕水貂催乳素分泌和黄体活动的抑制作用。另外，定时注射褪黑素可重现短日照对处于长日照条件下雌性动物的抑制作用。为了了解褪黑素分泌的昼夜变化是否是水貂测量日照长度机制的一部分，我们测量了交配后处于长日照或短日照条件下的完整雌性和去神经节雌性动物血浆褪黑素浓度的昼夜变化。根据Brun等人的方法[《生物科学进展》53:41 - 45]，采用放射免疫分析法测定褪黑素。在完整雌性动物中，白天血浆浓度范围从检测不到到40 pg/ml，在黑暗期开始后不久升高，并在午夜达到峰值。浓度升高的持续时间大致与夜晚长度成正比。在去神经节雌性动物中未检测到昼夜变化；褪黑素水平从未超过在完整雌性动物中观察到的白天值。
