Kamegai J, Minami S, Sugihara H, Hasegawa O, Higuchi H, Wakabayashi I
Department of Medicine, Nippon Medical School, Tokyo, Japan.
Endocrinology. 1996 May;137(5):2109-12. doi: 10.1210/endo.137.5.8612554.
GH feeds back on the hypothalamus and regulates its own secretion. We have previously shown that systemic administration of GH induces expression of the c-fos gene, a marker of neuronal activity, on the hypothalamic neuropeptide Y(NPY) and somatostatin neurons in rats. We argued that if GH were to act directly on NPY neurons, NPY neurons should express the GH receptor (GHR) gene. To test this hypothesis, coronal sections of the medial basal hypothalamus from adult male Wistar rats were processed by double label in situ hybridization using a 35S-labeled NPY complementary RNA probe and a digoxigenin-labeled GHR complementary RNA probe. In the medial basal hypothalamus, NPY messenger RNA (mRNA) was observed in the arcuate nucleus (ARC) and the dorsomedial nucleus. The majority (95%) of NPY mRNA-containing cells in the ARC expressed the GHR gene, whereas no NPY mRNA-containing cells in the dorsomedial nucleus expressed the GHR gene. These findings suggest that NPY neurons in the ARC mediate the feedback effect of GH on the hypothalamus.
生长激素（GH）作用于下丘脑并调节自身分泌。我们之前已经表明，对大鼠进行全身注射生长激素会诱导下丘脑神经肽Y（NPY）和生长抑素神经元中c-fos基因的表达，该基因是神经元活动的标志物。我们认为，如果生长激素直接作用于神经肽Y神经元，那么神经肽Y神经元应该表达生长激素受体（GHR）基因。为了验证这一假设，我们使用35S标记的神经肽Y互补RNA探针和地高辛标记的生长激素受体互补RNA探针，通过双重标记原位杂交技术对成年雄性Wistar大鼠下丘脑内侧基底部的冠状切片进行处理。在下丘脑内侧基底部，弓状核（ARC）和背内侧核中观察到了神经肽Y信使核糖核酸（mRNA）。弓状核中大多数（95%）含有神经肽Y mRNA的细胞表达生长激素受体基因，而背内侧核中没有含有神经肽Y mRNA的细胞表达生长激素受体基因。这些发现表明，弓状核中的神经肽Y神经元介导了生长激素对下丘脑的反馈作用。
