Adenosine triphosphate synthesis, mitochondrial number and activity, and pyruvate uptake in oocytes after gonadotropin injections

Objective: To determine the effects of gonadotropin injection on the energy generation of mature oocytes. Design: Randomized prospective study. Setting: Gamete and stem cell biotechnology laboratory at Seoul National University in Korea. Animal(s): Twelve- to 15-week-old golden hamsters (Mesocricetus auratus). Intervention(s): Injections of pregnant mare serum gonadotropin (PMSG; 5 or 15 IU), of hCG (5 or 15 IU), or of PMSG and hCG (15 IU of each; PMSG + hCG group) were administered to female hamsters. Main Outcome Measure(s): Adenosine triphosphate (ATP) synthesis, mitochondrial population number and activity, and pyruvate uptake were measured. Result(s): Significant (P<.05) differences were found in the ATP levels; compared with the control (no injection), a dramatic increase was detected after injections of 15 IU of hCG or of 15 IU of PMSG and 15 IU of hCG. In the same treatments, the mitochondrial population (mitochondrial DNA copy number) significantly increased, whereas mitochondrial activity measured by the ratio of activated to less-activated mitochondria did not change. A significant increase in pyruvate uptake was detected after the injections of 15 IU of PMSG and 15 IU of hCG. Conclusion(s): The change in ATP synthesis activity was a major cause for the adverse effect of gonadotropins on oocyte development in the hamster. The injections of 15 IU of hCG, or of 15 IU of PMSG and 15 IU of hCG, dramatically increased the ATP level, the mitochondrial population number, and pyruvate uptake. [Copyright &y& Elsevier]