Lack of effect of bovine pancreatic polypeptide on glucose production by isolated rat hepatocytes.

We have examined the possible influence of bovine pancreatic polypeptide (bPP) on glycogenolysis and gluconeogenesis in hepatocytes isolated from fed rats. The activity of glycogen phosphorylase a and pyruvate kinase, enzymes implicated in the hormonal regulation of these pathways, was also measured. Glycogenolysis was estimated by glucose release into the medium and gluconeogenesis by (U-14C) pyruvate incorporation into glucose. Addition of bPP to the incubation medium did not modify endogenous glucose production or glycogen phosphorylase a activity, either under basal conditions or on stimulation by glucagon (3 x 10(-10) M) or phenylephrine (10(-5) M). bPP also failed to alter both the incorporation rate of (U-14 C) pyruvate into glucose and pyruvate kinase activity, under basal conditions as well as in the presence of glucagon. Furthermore, time-course experiments revealed no effect of bPP on glycogen phosphorylase a or pyruvate kinase activities. These data indicate that pancreatic polypeptide is not implicated in the control of glucose production by isolated liver cells from fed rats.