Sirinathsinghji D J, Chen H Y, Hopkins R, Trumbauer M, Heavens R, Rigby M, Smith R G, van der Ploeg L H
Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, UK.
Neuroreport. 1995 Oct 23;6(15):1989-92. doi: 10.1097/00001756-199510010-00009.
We have studied by in situ hybridization histochemistry the mRNA expression of the c-fos immediate early gene in the brains of wild type and dwarf(dw/dw) and little(lit/lit) mutant mice after systemic injections of the synthetic GH secretagogues GHRP-6 and L-163,191. Both GH secretagogues induced a marked c-fos mRNA expression in the arcuate-ventromedial hypothalamus (ARC-VMH) of both control and mutant mice indicating a possible action on growth hormone releasing hormone (GHRH) neurones in the ARC-VMH. Both dw/dw and lit/lit mice showed a 5-fold elevation in GHRH mRNA expression in the ARC-VMH compared with control animals under basal conditions. Since lit/lit mice have a reduced ability to secrete GH and lack a functional GHRH receptor while dw/dw mice lack both GH and presumably GHRH receptors, the GH-secretagogue-induced c-fos mRNA in the brain of these mutants are unlikely to be mediated by an indirect action of GH or a interaction of the synthetic GH-secretagogue with the GHRH receptor.
我们通过原位杂交组织化学方法，研究了在野生型、侏儒（dw/dw）和矮小（lit/lit）突变型小鼠脑内，经全身注射合成生长激素促分泌素GHRP - 6和L - 163,191后，即刻早期基因c - fos的mRNA表达情况。两种生长激素促分泌素均在对照小鼠和突变型小鼠的弓状腹内侧下丘脑（ARC - VMH）诱导了显著的c - fos mRNA表达，表明其可能作用于ARC - VMH中的生长激素释放激素（GHRH）神经元。在基础条件下，与对照动物相比，dw/dw和lit/lit小鼠ARC - VMH中的GHRH mRNA表达均升高了5倍。由于lit/lit小鼠分泌生长激素的能力降低且缺乏功能性GHRH受体，而dw/dw小鼠既缺乏生长激素又可能缺乏GHRH受体，所以这些突变型小鼠脑内生长激素促分泌素诱导的c - fos mRNA不太可能由生长激素的间接作用或合成生长激素促分泌素与GHRH受体的相互作用介导。
