Objective: To prepare the cDNA probe of the steroidogenic acute regulatory (StAR) gene, and to investigate the StAR mRNA expression in stressed C57BL/6 mice leydig cells.
Methods: cDNA fragment encoding mouse StAR was amplified by RT-PCR from the total RNA prepared from the testis, and then the RT-PCR product was cloned into pCR2. 1-TOPO vector. After StAR gene cDNA was sequenced, the Dig-labeled cRNA probes for mouse StAR gene were prepared by in vitro transcription from cDNA fragment. With the specific cRNA probes, in situ hybridization analysis was conducted in stressed mice testis and controls.
Results: The results demonstrated that StAR mRNA levels were significantly lower in stressed leydig cells than that in controls (P < 0.05).
Conclusions: The decreased StAR mRNA levels induced by stress may result in a reduced production of StAR protein, which compromised the transportation of cholesterol, the substrate for androgen biosynthesis, into mitochondria, resulting in a poor T production in leydig cells and finally a declined T levels.