Evidence for a direct action of exogenous insulin on the pancreatic islets of diabetic mice: islet response to insulin pre-incubation.
Pancreatic islets were isolated by collagenase digest from normal (+/+) and severely diabetic (db/db) mice of the C57BL/Ks strain. Batches of islets from the diabetic mice were incubated for 1 h at 37 degrees C in Krebs-Ringer medium containing glucose (3 mmol/l), with or without mouse insulin (50 mU/l), before perifusion. When compared with untreated islets from the same digest, pre-incubation of islets from diabetic mice with insulin elicited a restoration of the biphasic insulin response to a glucose challenge which was indistinguishable from the response of the untreated, control islets from non-diabetic mice. Untreated diabetic islets showed no insulin response to glucose challenge, insulin values being very significantly lower than those of either non-diabetic or treated diabetic mouse islets (p = less than 0.005). The restoration of secretion in treated islets of diabetic mice was shown not to be an artefact. These observations provide evidence for a direct, as yet undefined, action of insulin on the beta cell of the diabetic mouse.
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese / Q000378:metabolism*; D009924:Organ Culture Techniques
D007328:Insulin; D005947:Glucose