hCG通过ERK1/2调节睾丸间质细胞StAR蛋白的表达

以2—3周龄的仔猪睾丸间质细胞为试验材料，研究了hCG在快速调节期对StAR蛋白表达的调节机制。结果表明：hCG、8-Br-cAMP均能使StAR蛋白、mRNA和P-ERK1／2的水平随刺激时间的延长逐渐增加，8-Br-cAMP作用的速度较hCG更快，增幅也更明显；加入PKI，StAR蛋白、mRNA和P-ERK1／2活性明显下降，但StAR mRNA仍然可以检测到；加入MAPK的抑制剂PD98059后，StAR蛋白、mRNA的水平均降低。由此可知，hCG在诱导StAR蛋白的表达过程中，首先通过cAMP—PKA直接调节蛋白前体蛋白向成熟蛋白的转化，随着时间的延长，通过cAMP-PKA-ERK1／2级联，磷酸化转录因子，促进StAR基因的表达。

hCG Regulating the Expression of StAR through ERK1/2 Pathway

Leydig cells from 2-3 week old piglets were used to study the mechanism of hCG regulating Steroidogenic acute regulatory protein(StAR).The results of this experiment were as shows :(1)Both of hCG and 8-Br-cAMP could enhance both the expression level of StAR protein and that of its mRNA,increase active ERK1/2 clearly depending on stimulating time.However,the effect of 8-Br-cAMP is faster than that of hCG.(2) While appending the inhibitior of PKA(PKI) to leydig cells in culture,both of the expression level of StAR protein and that of its mRNA began to drop significantly and the activity of ERK1/2 was inhibited but the level of StAR mRNA could still be detectable.(3) While appending the inhibitior of MAPK(PD98059),the expression level of StAR protein mRNA dropped significantly.These results inferred that at the beginning of hCG stimulating,hCG increased the level of StAR protein by cAMP-PKA.With the increase of time,hCG increased the level of StAR protein through cAMP-PKA-ERK1/2.