Pancreatic fate of 6-deoxy-6-[I-125]iodo-D-glucose - In vivo experiments

The fate of 6-deoxy-6-[I-125]iodo-D-glucose (6-DIG), injected intravenously , was compared in control rats and animals that had received streptozotocin and were then treated with insulin or not. In the control rats, the measur ement of plasma radioactivity suggested that, after an initial and rapid (u p to min 10) distribution phenomenon (K value: 12.2 x 10(-2) min(-1)), the clearance of the iodinated hexose occurred mainly by glomerular filtration (K value: 0.2 x 10(-2) min(-1)). Three minutes after the injection of 6-DIG , the radioactive content of muscle, liver, and pancreas, relative to the p aired value in blood, was lower in untreated diabetic rats than in control animals. In the case of muscle and liver, such a difference was no longer o bserved when the treatment of the diabetic rats by insulin resulted in rest oration of normoglycemia. In the pancreas, however, the radioactive content , whether expressed relative to the paired blood or liver value, remained s ignificantly lower in the insulin-treated diabetic rats than in the control animals. No significant difference between control and diabetic rats, in t erms of pancreatic radioactivity, was observed 10 min after the injection o f 6-DIG. These findings indicate that advantage can be taken from the vastl y different time course for 6-DIG uptake by pancreatic acinar and islet cel ls, as recently documented in vitro, to label preferentially the endocrine moiety of the pancreatic gland shortly after 6-DIG injection.