In vivo, meiotic maturation of the oocytes occurs within the follicle. However, in vitro, when oocytes are removed from the follicle, meiotic maturation resumes spontaneously. The relationship between developmental competence and oocyte development is unclear. However, it is hypothesized that if oocytes can be cultured in vitro under conditions that maintain meiotic arrest at the germinal vesicle (GV) stage, then they may have the opportunity to acquire greater developmental competence. buy prednisone
To date, treatment of oocytes with chemicals that elevate intracellular levels of cAMp, including dibutyryl cAMP, inhibitors of the cAMP-degrading enzyme phosphodiesterase, 3-isobutyl-1-methylxanthine activators of adenylate cyclase, for-skolin, cholera toxin, sodium fluoride, and prostaglandin E2, have been used in various species. According to several studies, treatments that maintain high levels of cAMP exert only a transient suppression of germinal vesicle breakdown (GVBD) in bovine oocytes. Most of these products are not compatible with long-term survival of the oocyte and therefore can not be used to enhance its developmental competence in culture.