Na+/H+ exchanger isoform-1 abundance in skin fibroblasts of type I diabetic patients with nephropathy.

In diabetic nephropathy and essential hypertension, the cellular Na+/H+ exchanger (NHE) exhibits increased activity. Whether this reflects increased numbers of NHE isoform-1 (NHE-1) transporters or increased turnover per molecule has not been established. We have used a specific polyclonal antibody directed toward the C-terminal of NHE-1 to measure NHE-1 content in cultured skin fibroblasts from diabetic patients with (DN) and without (DCON) nephropathy and normal controls (CON). NHE-1 content in fibroblasts from DN subjects was significantly less than that in the other two groups. This suggests that increased NHE activity in diabetic nephropathy is attributed to increased NHE-1 turnover per site rather than increased NHE-1 expression.