Growth factors and kidney development

The formation of the metanephric kidney is dependent upon the timed and sequential expression of a number of polypeptide growth factors. To shed light on the participation of members of the insulin-like growth factor (IGF) and epidermal growth factor/transforming growth factor- (EGF/TGF-) families, we measured the synthesis of IGF-I, IGF-II, EGF and TGF- by developing rat metanephroi in organ culture and determined the effect of anti-growth factor antibodies on growth and development. IGF-I, IGF-II and TGF- were produced by metanephroi and released into culture media. We could detect no EGF. Inclusion of anti-IGF-I, anti-IGF-II, anti-IGF-II receptor or anti-TGF- antibodies in organ cultures inhibited growth and development of metanephroi. Our findings suggest that both members of the IGF family and TGF- are produced within the developing metanephros and promote renal organogenesis.