In situ protein kinase C activity is increased in cultured fibroblasts from Type 1 diabetic patients with nephropathy

Aims/hypothesis. To verify whether individual susceptibility to diabetic nephropathy resides in an intrinsic difference in Protein Kinase C (PKC) activity. Methods. We compared the effect of different glucose concentrations on PKC activity, PKC isoform expression and diacylglycerol (DAG) content in cultured fibroblasts from 14 Type 1 diabetic patients who developed nephropathy with those in cells from 14 patients without nephropathy. We recruited 14 normal subjects as control patients. Forearm skin fibroblasts were cultured in either normal (5 mmol/l) or high (20 mmol/l) glucose concentrations. Results. In normal glucose, in situ PKC activity was higher in Type 1 patients with nephropathy (10.1±1.4 pmol/min/mg protein; p