Plasma levels of insulin, C-peptide and glucagon in liver cirrhosis.

Plasma levels of immunoreactive insulin (IRI), C-peptide and glucagon were assayed in 16 patients with liver cirrhosis and 9 control subjects after an oral glucose load (OGTT). Nine of the cirrhotics showed glucose intolerance, the remaining 7 cases showed normal OGTT. Both groups of cirrhotics showed high IRI and C-peptide values in basal conditions; peaks of these parameters, higher than those observed in the control subjects, were found during the OGTT. The C-peptide/IRI ratio, which was lower than normal both during fasting and after glucose load, presented the lowest values in patients with normal OGTT. In the conditions adopted for this study, glucagon showed higher plasma levels in all the cirrhotics studied than those found in the controls, but the highest levels were found in patients with normal OGTT. It can be concluded that the high levels of insulin found in liver cirrhosis are due to a beta-pancreatic hypersecretion (high C-peptide levels) but are also maintained by a decreased hepatic degradation of the hormone (C-peptide/IRI ratio below normal). Hyperglucagonemia is not the chief factor in determining the insulin-resistance observed in liver cirrhosis.