Lactation alters neuropeptide-Y and proopiomelanocortin gene expression in the arcuate nucleus of the rat.
Lactation alters neuropeptide-Y and proopiomelanocortin gene expression in the arcuate nucleus of the rat.
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DOI：
10.1210/endo.133.3.8365368
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发表时间：
1993-09
期刊：
影响因子：
4.8
通讯作者：
M. Smith
中科院分区：
文献类型：
--
作者：
M. Smith
为了确定可能参与GnRH神经元功能抑制的哺乳相关因素，我们研究了哺乳是否诱导弓状核神经元功能的变化，重点是神经肽Y（NPY）和POMC神经元活性的变化。在发情周期的非发情期第1天或产后第10天对动物进行研究。哺乳期动物在产后第2天将其窝仔调整为8只幼仔。脑组织被删除，以测量NPY肽含量在正中隆起（ME）或ME-弓状核（ME-ARC）和定量NPY或POMC mRNA的原位杂交，使用35 S标记的反义核糖核酸探针。NPY肽含量显着增加，在ME（1.8倍）和ME-ARC（1.5倍）在哺乳期间相比，那些间情期。整个ARC的NPY mRNA含量在间情期和泌乳期动物之间没有差异。然而，如果特定的细分的ARC进行了检查，显着增加（1.8倍）在ARC的ARC-C区域（在下丘脑背内侧核的平面）的NPY mRNA在哺乳期观察。在同一平面的ARC背侧，下丘脑背内侧核外侧的细胞中也有NPY表达的诱导。在弓状核ARC-C区的NPY mRNA的增加持续至少24小时后，去除吸吮刺激。ARC的其他细分没有表现出任何差异，在间情期和哺乳期之间的NPY mRNA。哺乳期POMC mRNA含量较间情期下降20-30%。哺乳减少POMC mRNA含量的影响并不特定于ARC的任何细分，但在整个ARC观察。鉴于哺乳是一种雌激素缺乏的状态，NPY神经元活性的增加，如ARC尾部基因表达的增加和ME含量的增加所示，可能在GnRH分泌的调节中起抑制作用。然而，POMC神经元活动的减少，如整个ARC的基因表达减少所示，似乎不参与GnRH神经元活动的抑制。ARC神经元功能的这些变化可能与哺乳期间调节食物摄入的激素变化或代谢信号有关。
To identify possible factors associated with lactation that may be involved in the suppression of GnRH neuronal function, we have examined whether lactation induces changes in arcuate nucleus neuronal function, focusing on changes in neuropeptide-Y (NPY) and POMC neuronal activity. Animals were studied during diestrous day 1 of the estrous cycle or during day 10 postpartum. Lactating animals had their litters adjusted to eight pups on day 2 postpartum. Brain tissue was removed to measure NPY peptide content in the median eminence (ME) or the ME-arcuate nucleus (ME-ARC) and to quantify NPY or POMC mRNA by in situ hybridization, using 35S-labeled antisense riboprobes. The NPY peptide content was significantly increased in the ME (1.8-fold) and ME-ARC (1.5-fold) during lactation compared to those on diestrus. The NPY mRNA content throughout the ARC did not differ between diestrous and lactating animals. However, if specific subdivisions of the ARC were examined, a significant increase (1.8-fold) in NPY mRNA in the ARC-C region of the ARC (at the plane of the dorsal medial hypothalamic nucleus) was observed during lactation. Dorsal to the ARC in this same plane, there was also an induction of NPY expression in cells lateral to the dorsal medial hypothalamic nucleus. The increases in NPY mRNA in the ARC-C region of the arcuate nucleus persisted for at least 24 h after removal of the suckling stimulus. The other subdivisions of the ARC did not show any differences in NPY mRNA between diestrus and lactation. The POMC mRNA content was decreased by 20-30% during lactation compared with that on diestrus. The effects of lactation to decrease POMC mRNA content were not specific to any subdivision of the ARC, but were observed throughout the entire ARC. Given that lactation is an estrogen-deficient state, the increase in NPY neuronal activity, as indicated by increased gene expression in the caudal portion of the ARC and increased content in the ME, could play an inhibitory role in the regulation of GnRH secretion. However, the decrease in POMC neuronal activity, as suggested by the decrease in gene expression throughout the ARC, would not appear to be involved in the suppression of GnRH neuronal activity. These changes in ARC neuronal function could be related to hormonal changes or metabolic signals regulating food intake during lactation.