Research ReportEffects of central gastrin-releasing peptide on glucose metabolism

- ICV administration of GRP causes an immediate hyperglycaemia.
- GRP induced hyperglycemia is accompanied by rise in EGP, plasma glucagon and insulin.
- Plasma corticosterone level remain unchanged during ICV infusion of GRP.

Gastrin-releasing peptide (GRP) mediated signals in the central nervous system (CNS) influence many functions associated with energy metabolism. The purpose of the present study was to investigate the central effect of GRP on glucose metabolism in the male rat. Intracerebroventricular (icv) administration of GRP caused an immediate hyperglycaemia which was sustained till the end of the infusion. The rise in plasma glucose levels was accompanied by an increase in endogenous glucose production (EGP), as well as increases in plasma glucagon and insulin concentrations. Furthermore, no differences in plasma corticosterone levels were noted between control and GRP treated rats. These results demonstrate that central GRP increases plasma glucose levels, probably by stimulating pancreatic glucagon release and concomitantly or subsequently endogenous glucose production.