Effect of highly purified porcine gut glucagon-like immunoreactivity (glicentin) on glucose release from isolated rat hepatocytes.

We studied the effect of the highly purified gut peptide glicentin on the glucose production and cyclic AMP accumulation of isolated rat hepatocytes. Glicentin at 2.10(-7) mol/l had the same effect on glucose production as maximally effective concentrations of glucagon, but did not stimulate cyclic AMP to the same extent; furthermore, glicentin apparently had only 1/100 of the potency of glucagon on glucose production. During incubation with hepatocytes glicentin was degraded to low molecular weight fragments one of which were chromatographically very similar to fragments of glucagon. It is suggested that glicentin exerts its glucagon-like effects on hepatocytes only after degradation to glucagon-like fragments. The results also demonstrate that the coupling between cyclic AMP accumulation and glucose production depends on the nature of the stimulatory peptide.