[Effect of annexin 5 on StAR and testosterone synthesis related enzyme in rat Leydig cells].

Objective: To investigate the effect of annexin 5 on the expressions at mRNA levels and protein levels of StAR, P450scc, 3β-HSD, 17α-hydroxylase and 17β-HSD in rat Leydig cells.

Methods: The primary rat Leydig cells were cultured for 24 h and then stimulated with 10(-9) mol/L annexin 5 for 12 h and 24 h respectively. Cellular total RNA and total protein were extracted respectively. The expressions of StAR, P450scc, 3β-HSD, and 17α-hydroxylase and 17β-HSD(10) mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR)and the protein levels were detected by Western blotting.

Results: Compared with the control group, at the mRNA level, after being treated with annexin 5 for 12 h, only 17β-HSD(10) expression had a 26% increase (P<0.05) while the others had no significant difference. The expressions of StAR, P450scc and 3β-HSD elevated 55%, 69% and 59%(P<0.05) respectively, and 17β-HSD(10) increased 104%(P<0.01) while 17α-hydroxylase had no significant difference after being treated with annexin 5 for 24 h. At the protein level, after being treated with annexin 5 for 12 h, 17β-HSD expression had a 39% increase (P<0.05). After 24 h, P450scc, 3β-HSD and 17β-HSD elevated 35%, 88% (P<0.05) and 47% (P<0.01) respectively while StAR had no significant difference.

Conclusion: Annexin 5 regulates testosterone synthesis by affecting the expressions of P450scc, 3β-HSD and 17β-HSD at gene and protein levels.