In vitro XXXX -induced meiosis in Rhinella arenarum oocytes: role of pre-MPF activation.

@entity251 @entity26725 @entity2494 @entity2671 @entity342 @entity195 @entity230 @entity3800 @entity479
In this work we showed the relationship between seasonal periods and the response of R. arenarum follicles and oocytes to different @entity230 . Using in vitro germinal vesicle breakdown (GVBD) assays, we demonstrated that P4 is the main @entity479 capable of inducing maturation in R. arenarum oocytes and follicles. In the second part of this work we showed that @entity3800 can activate pre-maturation promoting factors (pre-MPFs) such as P4, by cytoplasm microinjection experiments. The results indicated that the @entity230 assayed induced oocyte and follicle maturation in a dose- and time-dependent manner. In oocytes, P4 was the most efficient @entity479 as a maturation inducer (EC50 of the reproductive period, 6 nM, EC50 of the non-reproductive period     30 nM). @entity3800 ( @entity2494 , @entity2494 ; T, @entity251 ; and @entity195 , @entity2671 ) were less efficient maturation inducers than P4 (EC50 reproductive period     50, 120 and 600 nM respectively). Similar results were obtained with intact follicles in both seasonal periods. Although the response of follicles to the different @entity3800 was variable, in no case was it above the above the response induced by P4. Independently of the season, oocytes and follicles incubated in @entity26725 and T underwent GVBD after 6-10 h while oocytes and follicles incubated in @entity2494 and @entity195 matured more slowly. Furthermore, we demonstrated that microinjection of mature cytoplasm from @entity342 -treated oocytes is sufficient to promote GVBD in immature recipient oocytes ( @entity2494 , 57    12%; @entity195 , 60    8%; T, 56    13%). Thus, @entity3800 such as @entity2494 , T and @entity195 are as competent as P4 to activate pre-MPF.
