Importância das comunicações intercelulares para o desenvolvimento de folículos ovarianos

During the mammalian folliculogenesis, a long and complex process occurs, which the oocyte acquires the necessary competence for fecundation. In this process there is a metabolic bidirectional communication among the oocyte and somatic cells inside the follicle, which provides substrates for the oocyte developmental competence. This communication is mediated by cellular junctions (occlusions, adherens and gap junctions) localized in the transzonal projections. Cellular junctions and adhesion mollecules are responsable mainly for promoving the adhesion among follicular cells, however they can act in cellular signaling pathways and in regulation of genic transcription in the follicular cells and oocyte. Moreover, the communication junctions (gap junctions) are intermembrane channels that intermediate the communication among these cells through the passage of small molecules. These gap junctions are composed by connexins, of which the connexins 37 and 43 are the most frequently found in the ovarian follicle. Thus, knowledge of these cellular junctions are of great importance for studying the folliculogenesis process. The aim of this review was to report the main types of cellular junctions localized among the follicular cells, especially the gap junctions and the main membrane proteins (connexins) found in different stages of the follicular development.