P70S6K is involved in the inhibition of testosterone production in TM3 mouse Leydig cells overexpressing Cox7a2

Objective:To investigate the effects of Cox7a2 on the LH-induced testosterone production and the involved autophagy regulating signals in TM3 mouse Leydig cells.Methods: The Cox7a2-pEYFP-N1 fluorescent protein vector was constructed and transfected into TM3 mouse Leydig cells.The level of testosterone was determined by ELISA,and the effects of Cox7a2 on the expression of the steroidogenic acute regulatory protein(StAR) and the phosphorylation of the autophagy regulatory factor P70S6K were detected by Western blot.Results: LH stimulation increased the StAR protein expression and testosterone production,while Cox7a2 decreased P70S6K phosphorylation,reduced StAR expression and consequently inhibited LH-induced testosterone biosynthesis in the TM3 Leydig cells.Conclusion: Cox7a2 inhibits testosterone production by decreasing the StAR protein expression,which might be at least in part related with the activation of autophagy in TM3 mouse Leydig cells.