1. A three-step hyperinsulinaemic euglycaemic clamp was performed in six uraemic patients before dialysis and after 3 months of treatment with continuous ambulatory peritoneal dialysis, and in seven matched normal control subjects. Glucose turnover was assessed basally and during the clamp using [3-3H]glucose as a tracer.
2. The glucose infusion rate required to maintain euglycaemia was insignificantly higher in normal subjects compared with undialysed uraemic subjects at each insulin infusion rate.
3. The isotopically assessed total glucose turnover was also similar in normal and uraemic subjects. Basal hepatic glucose output was again similar in uraemic and control subjects and output was suppressed to a similar degree at each insulin infusion rate.
4. After treatment with continuous ambulatory peritoneal dialysis, the glucose infusion rate and the total glucose turnover during the clamp rose significantly at all three insulin concentrations (P < 0.05), but remained insignificantly different from normal control values. Hepatic glucose output was unchanged.
5. Peripheral insulin action was improved during continuous ambulatory peritoneal dialysis, but hepatic insulin action was unchanged.