Glomerular epithelial, mesangial, and endothelial cell lines from transgenic mice. The culture of glomerular cells has represented an important tool in the understanding of individual glomerular cell functions. However, the complexity of the glomerulus has made it difficult to obtain pure cell populations. It has also been difficult to culture glomerular endothelial cells, even as mixed cell populations. At present there are no established glomerular cell lines from any source. We have established permanent cell lines of cloned glomerular epithelial, mesangial, and endothelial cells from a line of mice transgenic for the early region of simian virus 40 (SV40). These mice appear normal at birth but by three to four months of age have sclerosis affecting a variable percentage of their glomeruli. The cells maintain features characteristic of their normal counterparts despite their transformed phenotype. These cell lines could be useful tools in understanding the pathogenesis of glomerulosclerosis in this transgenic mouse model and in studying those features of normal glomerular cell biology which are not altered by a transformed phenotype.