[Oocyte maturation. From animal experiments to human reproduction techniques].
The control of the oocyte growth and maturation are complex processus implicating endocrines (gonadotropines) and paracrine factors (growth factors, cytokines, steroids...), the paracrine regulation being under the endocrine control. The control of the cytoplasmic and nuclear maturation is realized by substances going through gap junctions from the follicular cells to the oocyte. Two of these substances, which are present in the follicular fluid, are responsible for maintaining the meiotic arrest: cyclic AMP and purines. Hormones or growth factors, which are able to affect the oocyte maturation both in vivo and in vitro, when they interact with their receptors stimulate enzymes which in turn stimulate the release of second messengers. Actually, the whole process that is oocyte maturation followed by fertilization in vitro does not give good results. This difficulty does not permit yet the freezing of immature oocytes which could be a solution in some cases encountered in Medically Assisted Procreation.
Lefèvre
B
B
INSERM Unité 355, Maturation Gamétique et Fécondation, et IFR sur les cytokines, Clamart.
D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D016207:Cytokines / Q000502:physiology; D004195:Disease Models, Animal; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development*; D012099:Reproductive Techniques; D015290:Second Messenger Systems / Q000502:physiology
D016207:Cytokines; D006133:Growth Substances; D000242:Cyclic AMP