Gomez G, Udupi V, Qi X, Lluis F, Rajaraman S, Thompson J C, Greeley G H
Department of Surgery, University of Texas Medical Branch, Galveston 77555, USA.
Am J Physiol. 1996 Sep;271(3 Pt 1):E582-6. doi: 10.1152/ajpendo.1996.271.3.E582.
The purpose of these studies was to examine the effects of excess growth hormone (GH) on gastrin and peptide YY (PYY) gene expression. Transgenic mice with the bovine GH gene linked to a mouse metallothionein I promoter were used as a model of chronic GH excess. Antral gastrin mRNA and peptide levels were elevated significantly (P < 0.05) in GH transgenic mice compared with wild type littermates. Ileal PYY mRNA and ileal and colonic PYY levels were significantly elevated in GH transgenic mice compared with wild type littermates. The elevations in gastrin and PYY gene expression in GH transgenic mice were independent of food intake. Serum concentrations of gastrin and PYY were also elevated in GH transgenic mice. Immunohistochemical analysis showed that the density of PYY-containing cells in the colon of GH transgenic mice and wild type littermates did not differ. In addition, the mRNA and protein levels of chromogranin A, a marker of endocrine cells, were not increased in the colon of GH transgenic mice. Together, these data indicate that GH, insulin-like growth factor I, or both can upregulate gastrointestinal gastrin and PYY gene expression directly.
这些研究的目的是检验过量生长激素（GH）对胃泌素和肽YY（PYY）基因表达的影响。将牛GH基因与小鼠金属硫蛋白I启动子相连的转基因小鼠被用作慢性GH过量的模型。与野生型同窝小鼠相比，GH转基因小鼠的胃窦胃泌素mRNA和肽水平显著升高（P<0.05）。与野生型同窝小鼠相比，GH转基因小鼠的回肠PYY mRNA以及回肠和结肠PYY水平显著升高。GH转基因小鼠胃泌素和PYY基因表达的升高与食物摄入量无关。GH转基因小鼠的血清胃泌素和PYY浓度也升高。免疫组织化学分析显示，GH转基因小鼠和野生型同窝小鼠结肠中含PYY细胞的密度没有差异。此外，GH转基因小鼠结肠中嗜铬粒蛋白A（一种内分泌细胞标志物）的mRNA和蛋白质水平没有升高。总之，这些数据表明GH、胰岛素样生长因子I或两者均可直接上调胃肠道胃泌素和PYY基因表达。
