Abstract: BACKGROUND AND AIM: To investigate the effects of thioglycolic acid on the activities of MAPK and MPF protein kinases during progesterone-induced Xenopus oocyte maturation process in vitro. MATERIALS AND METHODS: Xenopus oocytes were treated with TGA in vitro at dose of 0 μg/ml，5 μg/ml，25 μg/ml and 125 μg/ml, and samples collected at 4 h and 8 h after culture for Western Blotting detection of Erk1, p-Erk1, p-RSK, Cdc2, p-Cdc2 and cyclin B1 protein expressions. RESULTS: Obviously higher phosphorylation levels of Erk1 protein, indicated by the photodensity ratio of p-Erk1 and Erk1, and lower p-Cdc2 protein levels, compared with those of the control, were found in TGA-treated Xenopus oocytes at 4 h, accompanied by higher levels of p-RSK and Cyclin B1. However, there was no difference in these proteins,except higher p-Cdc2 phosphorylation and lower Cyclin B1 protein, between TGA-treated and control group at 8 h. CONCLUSION: TGA treatment could promote the activation of MAPK including its substrate RSK, and MPF at the early stage of maturation process. At the late stage, no evident impact was found of TGA on the activity of MAPK. There was obvious inhibition on MPF activity by TGA possibly through regulation of Cyclin B1 protein.

Key words: thioglycolic acid, oocytes, MAPK, MPF