Plasma insulin and C-peptide levels in cirrhotic and uremic patients.

Fifty grams of glucose were administered orally to twelve cirrhotics, twelve uremics and ten normal controls and the plasma insulin and C-peptide responses were measured and expressed as molar concentration. Glucose intolerance, hyperinsulinemia and elevated C-peptide levels were found in cirrhotics after glucose loading and in uremics during the later part of the glucose response. The molar ratio of C-peptide to insulin was lower in cirrhotics and higher in uremics than in controls. It is suggested that insulin is mainly degraded by the liver and C-peptide by the kidneys, and that C-peptide is not affected by the liver damage but is present in raised concentration in subjects with injured kidneys. Elevated C-peptide level in cirrhotics is consistent with hyperfunction of pancreatic B-cells.