Growth Factors in reproduction

What are Growth  factors?  Ans: These are  polypeptides in nature , exerts actions both on growth & dev of a cell. Growth factors have their own separate receptors at the cell surface mm and these are not be  confused with Vitamins / hormones but they act like by exerting paracrine and autocrine modes.  Besides there is yet another relevance of such G Factors. Those are key proteins in the  continuation of pregancy and any congenital deficiency(genetics )  may lead to  & Rec abortions.

Till date how many  G factors have been identified?? Total about 43, if I recall properly : - :- IGF-I & II, (action depends on IGF-BP-1 & 2), .Epidermal Growth Factors, Transforming Growth factor(TGF) , Fibroblast Growth factor, Platelate derived  Growth factor , Angiogenic Growth factor    ,The Interleukin –I system, Tumour Necrosis Factor-α,  many other peptides, Bone morphometric Factors,  Pro-renin,  Pro-opio-Melanocortin,  AMH –which is a transforming Growth factor-β family , OMI(oocyte Maturation Inhibitors, Preg Associated Plasma proteins, Endothelin-I, Antral Natriuretic peptide,  Inhibin-Activin-Follistatin, Renin-angiotensin system, Endogenous opiates, , GnRH like peptides, Colony stimulating Factors-though mainly synthesized in placenta.

Few relevant points on IGF-II ? Ans: It is synthesised at locally at G cells, theca cells and gonadotrophins stimulates IGF-II   synthesis   . IGF-II  stimulates cell proliferation, improves aromatase activity, promotes progesterone synthesis.

FSH inhibits both IGFI-BP & IGF-BB BP (binding proteins) à thereby FSH  control and make sure that free Growth  factors are made available to Follicles. Human Follicular fluid has maximum conc of IGF-II.