Increased action of pulsatile compared to non-pulsatile insulin delivery during a meal-like glucose exposure simulated by computerized infusion in healthy humans

Abstract

It has previously been demonstrated that pulsatile insulin has a greater hypoglycemic effect than non-pulsatile insulin during euglycemic conditions. The aim of the present study was to examine the effect of pulsatile versus non-pulsatile insulin delivery during a meal-like iv-glucose challenge. Ten healthy young subjects were examined on two occasions. A pancreatic–pituitary clamp was maintained with somatostatin infusion and replacement of glucagon and growth hormone at baseline levels. During the first three hours on both study days, insulin was infused in a pulsatile manner. Hereafter glucose and insulin were infused by computer-controlled pumps for four hours in a pattern mimicking the postprandial glucose and insulin profiles. At one study day, insulin infusion was done in a continuous manner, while at the other study day this profile was done in a pulsatile pattern. The hypoglycemic effect of insulin was measured as the integrated area under the curve of glucose during the four-hour infusion period. The mean insulin concentration measured as the integrated area under the curve was identical (P > .9). The hypoglycemic effect of insulin was significantly augmented by 13% during pulsatile delivery as compared to continuous delivery (P = .015). Likewise was the maximal glucose concentration significantly lower at the day of the pulsatile profile (9.9 ± 1.0 vs. 11.4 ± 2.3mmol/l, P = .036). Pulsatile insulin release plays an important role in the postprandial glucose homeostasis. The disturbed insulin pulsatility in type 2 diabetes mellitus may contribute to the postprandial hyperglycemia.