Immunoelectron microscopy of epidermal growth factor in mouse kidney.

We recently have reported the immunolocalization of epidermal growth factor (EGF) in mouse kidney by light microscopy. In the present study, we have investigated the ultrastructural localization of EGF by the preembedding immunoperoxidase method for electron microscopy. EGF immunoreactivity was present on the apical plasma membrane of the cells of the thick ascending limb of Henle and the distal convoluted tubule. The macula densa, by contrast, lacked immunoreactivity. Based on functional evidence, a possible regulatory role for EGF in the membrane transport in the distal nephron has been suggested.