IGF-I和hCG对大鼠Leydig细胞葡萄糖转运蛋白基因表达调控研究

Regulation of GLUT Gene Expression by IGF-1 and hCG in Adult Rat Leydig Cells

背景与目的:研究胰岛素样生长因子-I(Insulin-likegrowthfactor-I,IGF-I)和人绒毛膜促性腺激素(humanChorionicGonadotropin,hCG)对成年大鼠Leydig细胞中葡萄糖转运蛋白(Glucosetransporters,GLUTs)基因表达的影响,为进一步探讨Leydig细胞中睾酮的合成与葡萄糖代谢关系提供依据。材料与方法:采用改良的Klinefelter方法从成年大鼠睾丸中分离获得Leydig细胞,并用反转录-聚合酶链技术检测IGF-I和hCG对Leydig细胞中GLUTs基因表达的调控作用。结果:分离得到纯度为98%的Leydig细胞,与空白对照组相比,hCG可显著增加Leydig细胞中GLUT8基因mRNA的表达,并且此作用具有剂量依赖性与时效性。100ng/mlIGF-I可显著增加Leydig细胞中GLUT8基因mRNA表达,并且IGF-I可和hCG协同作用,显著提高GLUT8基因mRNA表达,该结果与100ng/mlIGF-I和10ng/mlhCG协同作用显著增加睾酮合成的结果相吻合。然而,在大鼠Leydig细胞中,无论是10ng/mlhCG或100ng/mlIGF-I单独作用或同时作用于细胞,都不影响GLUT1和GLUT3基因mRNA水平。结论:在成年大鼠Leydig细胞中,IGF-I和hCG对细胞中GLUT8基因表达的调节作用具有特异性,IGF-I和hCG能协同作用显著提高细胞GLUT8基因mRNA水平,从而增强细胞摄取葡萄糖的能力,可为细胞提供更多的代谢能源,最终增加了Leydig细胞睾酮合成与分泌。

BACKGROUND AND OBJECTIVE: To study the effects of insulin-like growth factor-I(IGF-I)and human chorionic gonadotropin(hCG)on expressions of glucose transporters(GLUTs)gene and testosterone production in adult rat Leydig cells and the relationship between steroidogenesis and glucose metabolism in adult rat Leydig cells. MATERIAL AND METHODS: The rat Leydig cells were isolated using modified Klinefelter’s method.The regulatory effects of IGF-Ⅰand hCG on GLUTs gene expression in primary cultured rat Leydig cells were investigated by RT-PCR. RESULTS: The rat Leydig cells with the purity of98%were isolated.hCG caused dose- and time-dependent increases of GLUT8mRNA levels.IGF-I(100ng/ml)could also increase GLUT8mRNA expression significantly.IGF-I and hCG had synergistic effects on GLUT8mRNA expression(P<0.001).This result was consistent to the result from the experiment in which IGF-I(100ng/ml)and hCG(10ng/ml)can increase testosterone level synergistically(P<0.001).However,in primary cultured rats Leydig cells,neither GLUT1nor GLUT3mRNA expression was affected by the treatment with hCG(10ng/ml),IGF-I(100ng/ml),or the combination of hCG(10ng/ml)and IGF-I(100ng/ml). CONCLUSION: In adult rat Leydig cells,regulatory effects of IGF-I and hCG on GLUT8mRNA expression are specific.IGF-I and hCG can significantly increase GLUT8mRNA expression level synergistically.