Purine metabolism is known factor for nuclear maturation of oocytes through both follicle cells and oocyte itself. However, it is largely unknown the roles of purine metabolism in the oocyte competence for fertilization and early development. In this study, the effects of adenosine in oocyte competence for development were examined using adenosine and its synthetic inhibitors. Adenosine treatment from GV intact stage for 18 hr (fGV) caused of decrease the fertilization rate but of increase the cleavage rate compared from the other stage treatment groups. Hadacidin did not effect on fertilization rate but increased cleavage rate without stage specificity. Adenosine did not block the effects of hadacidin with the exception of fGV group. By the inhibition of purine synthetic pathways the fertilization rate was decreased in the fGV and fGVB groups but increased in the fMII group. Exogenous adenosine caused of decrease fertilization rate in the fGVB group but increase in the fMII group. Cleavage rate was dramatically increased in the adenosine treatment with synthetic inhibitors. It means that the metabolism of purine has stage specific effects on fertilization and cleavage. Exogenous adenosine had only can improve oocyte developmental competence when it treated at GV intact stage. On the other hand, endogenous synthesis in all maturation stage caused of increase the cleavage rate without effects on fertilization. These data suggest that adenosine at GV stage as a paracrine fashion and inhibitions of endogenous adenosine in all stage improve oocyte developmental competence..

INTRODUCTION
 MATERIALS AND METHODS
  1. Animals
  2. Oocyte collection and in vitro maturation (IVM)
  3. IVF and embryo culture
  4. Statistical analysis
 RESULTS
  1. Exogenous adenosine has no effect after GVB on
  2. Adenosine de novo inhibition enhancing thecleavage rate
  3. Exogenous adenosine did not overcome with theconcentration compensation manners of the hadacidineffects
  4. Purine synthesis had maturation stage specificeffects on oocyte developmental competence
 DISCUSSION
 REFERENCES

• Yong-Pil Cheon(Division of Development and Physiology, Department of Biology, Institute for Basic Sciences, Sungshin Women’s University) Corresponding Author