Abstract
Changes in canine plasma glucose, immunoreactive glucagon (IRG), pancreatic polypeptide (PP) and insulin (IRI) were studied during the acute development of diabetes mellitus after iv alloxan injection. 10 mg or 75mg/kg body weight of alloxan was injected iv and blood was taken successively till one or two days later. Plasma glucose showed four phases: first immediate and moderate decreaseappeared 30 min after injection, second initial hyperglycemic phase, third hypoglycemic and fourth diabetic ones. Plasma IRIhadalready increased to 182±60μU/ml 10 min after injectionand again began to increase after about 6 h, peaking to 134±49μU/ml at 18 h. Plasma IRG began increasinggradually soon after alloxan injection. The initial value was 196±26pg/ml and it increased to 534±144pg/ml at 4 h during the initial hyperglycemic phase, then reached a higher level through the hypoglycemic and diabetic phases. The change in plasma PP was similar to that in IRG. The initial value was 256±95 pg/ml at 12 h after injection, peaking to 840±100 pg/ml in the hypoglycemic phase. Similar blunted values were obtained following 75mg/kg alloxan injection.
Thus not only plasma IRI but also plasma IRG and PP varied greatly during the acute development of alloxan diabetes and somecontribution of IRG to the initial hyperglycemic phase was suggested.
