1. Methylxanthines (IBMX, caffeine, theophylline), which are known inhibitors of c-AMP phosphodiesterase inhibited reversibly progesterone-induced maturation of Xenopus oocyte. 2. The time course of protein phosphorylation during maturation stimulated by progesterone was analysed in Xenopus oocyte : protein phosphorylation increased around germinal vesicle breakdown (GVBD). No quantitative chan...

During follicular atresia in the sheep and pig there is a marked reduction in the vasculature of the theca interna underlying the membrana granulosa. In the sheep there is no reduction of thecal blood vessels adjacent to the cumulus which remains viable. By contrast, in the pig the cumulus degenerates during atresia and the underlying thecal vasculature is greatly diminished. However, despite l...

Background: Polarized cells are key to the process of differentiation. Xenopus oocyte is a polarized cell that has complete blue-print to differentiate 3 germ layers following fertilization, as key determinant molecules (Proteins and RNAs) are asymmetrically localized. The objective of this work was to localize Na+, K+-ATPase activity along animal-vegetal axis of polarized Xenopus oocyte and fo...