Separation of proximal tubule cells from suspensions of rat kidney cells by free‐flow electrophoresis

Suspensions of rat kidney cells obtained by disaggregation of the kidney with 0.25% trypsin were separated by electrophoresis. Previously, we found a correlation between cells with histochemically demonstrable alkaline phosphatase (HDAP) and cells with brush borders which established that HDAP is a useful marker for rat proximal tubule cells (Kreisberg et al., '77). The starting suspension of cells for electrophoresis consisted of 38.4 ± 5.7% nucleated cells with HDAP, 39.8 ± 5.7% nucleated cells without HDAP, and 20.8 ± 9.2% red blood cells. After electrophoresis, the purest fraction contained 85.8 ± 3.5% nucleated cells with HDAP, 8.4 ± 2.2% nucleated cells lacking HDAP, and 5.8 ± 2.8% red blood cells; 91.9 ± 2.4% of the nucleated cells in the purest fractions had HDAP.