Effect of perchlorate on glucose-stimulated insulin release and 45Ca2+ uptake in pancreatic islets from diabetic Chinese hamsters.

Insulin release and 45Ca2+ uptake were studied in isolated islets from Chinese hamsters of genetically diabetic and normal sublines. The calcium channel agonist, perchlorate (ClO4-, 12 mmol/L), augmented both 45Ca2+ uptake and insulin release from normal islets in the presence of 20 but not 1 mmol/L glucose. The agonist also amplified the glucose-stimulated 45Ca2+ uptake and insulin release from diabetic islets but did not normalize the insulin release despite normal insulin concentration in the diabetic Chinese hamster islets. The dry weight of the diabetic islets was subnormal (54%, p < 0.005) but the insulin concentration (insulin per dry weight of islet tissue) was not different from normal (122%). It appears that there are defective mechanisms in addition to the glucose-stimulated influx of Ca2+ in diabetic islet B cells.