Phelps C J, Dalcik H, Endo H, Talamantes F, Hurley D L
Department of Anatomy, Tulane University School of Medicine, New Orleans, LA 70112.
Endocrinology. 1993 Dec;133(6):3034-7. doi: 10.1210/endo.133.6.7694848.
Hypothalamic expression of growth hormone-releasing hormone (GHRH) was quantified morphologically in dwarf mice which exhibit spontaneous genetic GH absence. Mouse GHRH mRNA was assessed by in situ hybridization; densitometric evaluation of total mRNA in dwarfs showed levels 2.3-fold higher than in phenotypically normal siblings (p < 0.01); assessment of mRNA per neuron by autoradiographic grain counting indicated a 2.5-fold increase per cell in dwarfs (p < 0.005). GHRH peptide was evaluated immunocytochemically using a new mouse-specific antiserum; numbers of neurons containing detectable levels were 3-fold higher in dwarfs (p < 0.005). The increase in GHRH mRNA corroborates that reported previously in the GH-deficient little mouse, and after hypophysectomy in rats; GHRH peptide increase contrasts with previous reports of the effect of acute GH removal by hypophysectomy, in which GHRH levels fell. The results suggest that chronic GH deficiency is accompanied by increased translation as well as transcription of GHRH.
在表现出自发性遗传性生长激素（GH）缺乏的侏儒小鼠中，对生长激素释放激素（GHRH）的下丘脑表达进行了形态学定量分析。通过原位杂交评估小鼠GHRH mRNA；对侏儒小鼠总mRNA的光密度测定评估显示，其水平比表型正常的同胞小鼠高2.3倍（p < 0.01）；通过放射自显影颗粒计数评估每个神经元的mRNA，结果表明侏儒小鼠每个细胞增加了2.5倍（p < 0.005）。使用一种新的小鼠特异性抗血清通过免疫细胞化学方法评估GHRH肽；在侏儒小鼠中，含有可检测水平的神经元数量高3倍（p < 0.005）。GHRH mRNA的增加与先前在生长激素缺乏的矮小症小鼠以及大鼠垂体切除术后所报道的情况相符；GHRH肽的增加与先前关于垂体切除术后急性去除生长激素的影响的报道形成对比，在先前的报道中生长激素释放激素水平下降。结果表明，慢性生长激素缺乏伴随着生长激素释放激素的翻译以及转录增加。
