1. The effect on hormonal status and intermediary metabolism of a single 6 h dialysis cycle at two different concentrations of dialysate glucose was investigated in six patients on continuous ambulatory peritoneal dialysis.
2. The basal blood glucose level was elevated by 0.5 mmol/l, associated with a threefold increase in basal serum insulin compared with seven normal controls. Blood glucose and serum insulin rose further during dialysis, particularly with hypertonic (215 mmol of glucose/l) dialysis fluid and levels remained high for 6 h after the onset.
3. Plasma glucagon concentrations were 2.7-fold increased and did not decrease to normal during dialysis.
4. Concentrations of the gluconeogenic precursors lactate and alanine were consistently raised, and levels of circulating non-esterified fatty acids and ketone bodies were lowered, particularly with hypertonic dialysis fluid.
5. The long-term effects of sustained hyper-insulinaemia, including suppression of lipolysis and ketogenesis, require further investigation.