Fig. 7

PS-MPs decreased the level of StAR by inhibiting the AC/cAMP/PKA pathway. Primary Leydig cells were exposed to various concentrations of 0.5 μm PS-MPs for 24 h. A AC kinase activity was measured by an AC activity assay kit (n = 3). Results are expressed as means ± SD. *P < 0.05, **P < 0.01 vs. control. B The content of cAMP was detected by ELISA (n = 3). Results are expressed as means ± SD. *P < 0.05, **P < 0.01 vs. control. C PKA kinase activity was examined by a PKA activity assay kit (n = 3). Results are expressed as means ± SD. *P < 0.05, **P < 0.01 vs. control. (D, E) The expression of PRKACA and PRKACB in cells was analyzed by western blotting. The expression levels were quantified with ImageJ and expressed as means ± SD (n = 3). Results are expressed as means ± SD. *P < 0.05, **P < 0.01 vs. control. (F, G) Leydig cells were incubated with 0.2 mg/mL PS-MPs for 1 h and then cultured in serum-free medium in the presence of 20 mM forskolin for another 24 h. The expression of StAR in cells was analyzed by western blotting. The expression levels were quantified with ImageJ and expressed as means ± SD (n = 3). Results are expressed as means ± SD. **P < 0.01 vs. control; ^#P < 0.05 vs. forskolin treatment group. (H, I) Leydig cells were incubated with 0.2 mg/mL PS-MPs for 1 h and then cultured in serum-free medium in the presence of 0.1 mM 8-bromo-cAMP for another 24 h. The expression of StAR in cells was analyzed by western blotting. The expression levels were quantified with ImageJ and expressed as means ± SD (n = 3). Results are expressed as means ± SD. **P < 0.01 vs. control; ^#P < 0.05 vs. 8-bromo-cAMP treatment group