Effect of neurotensin on glucose and insulin portal blood levels in hyperglycemic rats.

A new multiple sampling technique for obtaining blood from the portal vein has been used to investigate the effects of neurotensin on insulin and glucose portal blood levels in rats rendered hyperglycemic by a constant glucose infusion. The peptide has been first injected acutely (2 microgram/rat iv), and then constantly infused (0.5 microgram/min for 55 min). The preliminary results indicate that no effect of the acute injection could be observed, but hyperglycemia and hyperinsulinemia were induced by the constant infusion of the peptide. It is suggested that neurotensin may stimulate the release of insulin probably through a direct mechanism.