BLOOD SUGAR AND PLASMA INSULIN RESPONSE TO STIMULATION OF ENDOGENOUS SECRETIN RELEASE

The effect of endogenous secretin released after intraduodenal instillation of 10 mval HCl/10 min and of exogenous seoretin (Boots) 1 U/kg body weight, on exocrine and endocrine pancreatic function was examined in 6 subjects. Although stimulation of exocrine secretion was observed during instillation of HCl as well as after i.v. administration of secretin, a β-cytotropic effect, as estimated from blood sugar and plasma insulin concentrations in peripheral venous blood, was demonstrable only following exogenous secretin. - In 7 subjects, intraduodenal instillation of 2 × 3 mval HCl during intraduodenal glucose loading with 300 ml 5% glucose/ 20 min, did not result in any change of the blood sugar curve and of the insulin values compared with intraduodenal instillation of 2 × 30 ml 0.9% NaCl with the glucose. Lastly, no β-cytotropic effect could be detected following the intraduodenal instillation of 3 ml ether, which stimulated secretion of a pancreatic juice rich in bicarbonate and enzymes. Thus endogenous secretin may be without appreciable physiological significance, with regard to the better assimilation of glucose and increased insulin secretion after oral glucose loading compared with intravenous glucose. © 1969 Springer-Verlag.