Arita J, Kawakami M
Endocrinol Jpn. 1981 Dec;28(6):769-74. doi: 10.1507/endocrj1954.28.769.
In the present study, the role of the medial preoptic area (MPO) in the neural control of the nocturnal prolactin (PRL) surge was investigated in ovariectomized rats. Cervical stimulation (CS) or bilateral MPO lesions caused a marked nocturnal PRL surge at 0400 h on the fourth day after CS or the lesions in ovariectomized rats in which blood samples were obtained by decapitation. However, operation for indwelling a catheter and serial blood collection completely eliminated the MPO lesion induced nocturnal surge while they did not affect the CS-induced surge. On the other hand, MPO lesions could not induce the nocturnal PRL surge in neonatally androgenized female rats. These results suggest that the MPO not only tonically inhibits the initiation of the nocturnal PRL surge but also has a buffer action on the PRL surge-suppressing action of stress. Furthermore, it may be possible that the failure of CS to initiate and maintain the nocturnal PRL surge in neonatally androgenized rats is not due to the inability of CS to disinhibit the inhibitory action of the MPO, but rather due to the extinction of the circadian rhythm itself of the nocturnal PRL surge in these rats.
在本研究中，我们在去卵巢大鼠中研究了内侧视前区（MPO）在夜间催乳素（PRL）分泌高峰神经控制中的作用。在去卵巢大鼠中，进行颈刺激（CS）或双侧MPO损伤后，于CS或损伤后第4天的04:00时出现明显的夜间PRL分泌高峰，这些大鼠通过断头采集血样。然而，留置导管手术和连续采血完全消除了MPO损伤诱导的夜间分泌高峰，而它们并不影响CS诱导的分泌高峰。另一方面，MPO损伤不能诱导新生雄激素化雌性大鼠出现夜间PRL分泌高峰。这些结果表明，MPO不仅持续抑制夜间PRL分泌高峰的起始，而且对压力抑制PRL分泌高峰的作用具有缓冲作用。此外，CS在新生雄激素化大鼠中未能启动和维持夜间PRL分泌高峰，可能不是因为CS无法解除MPO的抑制作用，而是由于这些大鼠夜间PRL分泌高峰的昼夜节律本身消失。
