Effects of intra-abomasal infusion of ß-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 ß-casomorphins (ß-casomorphin-4-amide, -5 and -7) was given via an abomasal infusion line. The ß-casomorphins significantly lowered the responses of serum insulin to both abomasal and intravenous glucose infusions (P <0.05). However, the ß-casomorphins did not significantly affect circulating glucose concentrations. The insulinopenic action of the ß-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.