Effects of intra-abomasal infusion of β-casomorphins on circulating concentrations of hyperglycaemic insulin and glucose in dairy cows

The effects of intra-abomasal infusion of a mixture of -casomorphins on circulating concentrations of insulin and glucose prestimulated by either abomasal (experiment 1) or intravenous (experiment 2) glucose were studied using non-lactating dairy cows. In both experiments, bolus infusion of 240 mg of a mixture of three beta -casomorphins (beta -casomorphin-4-amide, -5 and -7) was given via an abomasal infusion line. The beta -casomorphins significantly lowered the responses of serum insulin to both abomasal and intravenous glucose infusions (P < 0.05). However, the <beta>-casomorphins did not significantly affect circulating glucose concentrations. The insulinopenic action of the beta -casomorphins is consistent with the action of somatostatin-28 (SS-28) as judged from the effects of SS-28 on the insulin secretion when administered intravenously in experiment 1. (C) 2000 Elsevier Science Inc. All rights reserved.