Abstract:

【Objective】The objective of the study was to identify whether the combination of FSH and 17β-estradiol regulates the expression of S-Phase kinase-associated proteins2 (Skp2) in cultured immature boar sertoli cell via extracellular signal-regulated kinase1/2 (ERK1/2).【Method】The cultured immature boar sertoli cells were treated with the combination of 17β-estradiol (10-9 mol·L-1) and FSH (50 ng·mL-1), in addition to a variety of signaling pathway inhibitors and Western blotting, Real-time PCR was applied to detect the expression of Skp2 protein and mRNA, respectively.【Result】Treatment with combined FSH and 17β-estradiol increased the concentration and mRNA abundance of Skp2 from 15 mins to 90 mins, and these activities peaked at 30 mins in comparison to the controls (P＜0.05). FSH (50 ng·mL-1), 17β-estradiol (10-9 mol·L-1) and forskolin alone increased the amount of Skp2 protein and the abundance of Skp2 mRNA (P≥0.05 for all). Rp-cAMP (cAMP inhibitor), H-89 (protein kinase A inhibitor), verapamil (L-type Ca2+ ionic channel inhibitor) and U0126 (ERK1/2 inhibitor) impaired the effect of combined FSH and 17β-estradiol on the expression of Skp2 in both protein and mRNA levels (P＜0.05), however, no significant effects were found on the expression of Skp2 in both protein and mRNA levels when they were tested alone. Likewise, there was no significant effects on activity of ERK1/2 by using H-89 and verapamil alone, but the activity of ERK1/2 was impacted by combination of FSH 17β-estradiol, H-89 and verapamil (P＜0.05).【Conclusion】cAMP-PKA pathway and Ca2+influx are activated by the combination of FSH and 17β-estradiol, and both of them are associated with ERK1/2 activation, which regulates the expression of Skp2.

Key words: FSH, 17β-estradiol, sertoli cell, S-phase kinase-associated proteins2, extracellular signal-regulated kinase1/2