Endocrine Abstracts

This is the review of original data concerning the role of some metabolic hormones (GH, leptin, ghrelin, obestatin), growth factors (IGF-I, IGFBPs, EGF, thrombopoietin), intracellular mediators of their action (cyclic nucleotides, protein kinases, PKA, MAPK, CDK, transcription factors, CREB, STAT-1, p53 and related cDNA, siRNA and miRNA gene constructs) on basic ovarian functions (cell proliferation, apoptosis, secretion, oogenesis, ovulation, production and viability of pups) in different species (pig, rabbit, humans and chicken). These hormonal and intracellular regulators are able to control apoptosis, proliferation and secretory activity in porcine, rabbit, human and chicken ovarian cells and maturation of porcine oocytes and cumulus oophorus in vivo and in vitro, as well as to suppress or promote the response of ovarian cells to other hormones. Immuno-blockade of these hormones prevented their effects. Effects of hormones on ovarian cells were associated with changes in protein kinases and transcription factors in such cells, whilst blockers of kinases prevented or promoted hormones action. Transfection of granulosa cells with gene constructs for some transcription factors affected ovarian cell functions and modify hormones action. Down-regulation of approximately 1/3 known protein kinases by specific siRNA constructs resulted decrease in accumulation of these kinases within granulosa cells and changes in expression of kinase-dependent transcription factors, markers of cell proliferation, apoptosis and release of steroid hormones and IGF-I. Transfection of granulosa cells with constructs up and down regulating expression of some miRNAs are able to alter ovarian cell proliferation, apoptosis, as well as the hormone release. In vivo experiments demonstrated that leptin, IGF-I, steroid hormones and some regulators of PKA, MAPK and CDK could be used to predict reproductive efficiency, for direct in vitro control of maturation of oocytes and for in vivo stimulation of reproduction. Therefore, metabolic hormones, growth factors and intracellular regulators and mediators of their action (protein kinases, transcription factors, siRNAs, miRNAs) can be used for characterization of state of ovarian cells, for identification signaling pathways controlling reproductive processes, as well as for prediction and control of basic ovarian cell functions.