M-phase promoting factor (MPF) and mitogen activated protein kinases (MAPK) activities of domestic cat oocytes maturedin vitroandin vivo

This work was undertaken in order to examine M-phase promoting factor (MPF) and mitogen-activated protein kinases (MAPK) activities during meiotic progression of cat oocytes cultured in two different media for two different incubation times and preovulatory cat oocytes that reached MIIin vivo. Oocytes recovered from ovaries of ovariectomized cats were cultured either in TCM 199 or SOF for 24 h and 40 h.In vivomatured oocytes were recovered by follicular aspiration from ovaries of domestic cats ovariectomized 24 h to 26 h after hormonal treatment. Results showed that the kinetic of MPF and MAPK activity was similar during meiotic progression of cat oocytes matured in TCM 199 and SOF. After 24 h of incubation, MII oocytes had significantly (p< 0.001) higher MPF and MAPK levels than MII oocytes cultured for 40 h in both culture media. MPF and MAPK activity was significantly (p< 0.01) lower in the oocytes maturedin vitrothan in those maturedin vivo. This study provides evidence that the two different maturation media did not determine differences in MPF and MAPK fluctuations and levels during meiotic progression of cat oocytes and that the time of maturation influenced the level of the two kinases. Moreover, it shows that MPF and MPK activity is higher inin vivomatured oocytes than inin vitromatured oocytes, suggesting a possible incomplete cytoplasmic maturation after culture.