Effect of insulin on motilin release in man.

Abstract

The effect of insulin on motilin release was investigated by use of the euglycemic glucose clamp technique. By use of this technique plasma glucose concentration was maintained constant at 80-90 mg/100 ml, and plasma insulin immunoreactivity (IRI) was increased from 15±6,uU/ml to 171±22 pU/ml in 10 min, and remained at this level for 2 hr. Plasma motilin like immunoreactivity (ML) concentration decreased within 10 min from 199±36 pg/ml to 120+28 pg/ml and remained low during the course of study. A significant negative correlation between MLI and IRI concentrations (r = -0.72, p <0.01) was observed. The present results indicate that the suppressive effect of insulin on motilin release is a direct action of insulin and is not mediated by glucose.insulin ; motilinMotilin, a 22 amino-acid peptide hormone has been known as one of the gut hormones which affect the motility of the stomach and intestine (Brown et al. 1971;Lee et al. 1974;Jennewein et al. 1975). It has been shown that intraduodenal administration of glucose and amino-acids solution, which increase insulin release, inhibit the release of endogenous motilin (Christofides et al. 1979). We have shown that following insulin administration plasma motilin-like immunoreactivity (MLI) concentration fell sharply in healthy subjects and diabetic patients with and without autonomic neuropathy (Funakoshi et al. 1982). The fall of plasma MLI concentration was not correlated with changes in plasma glucose and it may have been due to the direct action of insulin on the inhibition of MLI release.The present study was designed to examine the effect of insulin on MLI release during maintaining blood glucose at a constant level utilizing the glucose clamp technique. The present study clearly demonstrated that it is the increase

Motilin: from gastric motility stimulation to hunger signalling

“…However, neither glucose nor insulin affects motilin secretion from human duodenal mucosa biopsy samples, indicating that their effect on motilin release is indirect. The inhibitory effect of insulin on motilin release in humans seems to be glucose-independent, as shown by using an euglycaemic glucose clamp 164 . Administration of xylitol, a low-caloric sweetener with minimal effects on insulin secretion, increased rather than decreased plasma levels of motilin 165 .…”

“…While motilin influences insulin secretion, insulin also alters motilin secretion. In humans, an inverse correlation has been shown between motilin and glucose and motilin and insulin during the postprandial state 50,54,164 . However, neither glucose nor insulin affects motilin secretion from human duodenal mucosa biopsy samples, indicating that their effect on motilin release is indirect.…”