Since glomerular development is regarded as angiogenesis/vasculogenesis, there should be angiogenic cytokines which mediate glomerulogenesis. In the developing kidney, messages of vascular endothelial growth factor (VEGF) and its receptors are expressed in epithelial and endothelial cells of the glomerulus, respectively. In vivo, suppression of VEGF activity by neutralizing antibody seriously interrupts glomerulogenesis. Typically, there are no endothelial cells in the abnormal glomerulus. Structural changes of the glomerulus were clear by observing vascular castings of renal vessels. Although structures of arteries and arterioles were not impaired, the capillary lumen of the glomerulus was completely lost or interrupted halfway through development. It is concluded that VEGF is secreted from the Bowman's capsule, and stimulates endothelial or endothelial progenitor cells in a paracrine fashion to form the glomerulus.