Proinsulin biosynthesis by pancreatic islets of the rat and the study of alloxan cytotoxicity in vitro.

Incorporation of L-[4,5-3H] leucine into proinsulin plus insulin by isolated pancreatic islets was shown to be severely inhibited by previous brief exposure to 1.25 mM alloxan, but incorporation into other islet proteins was not affected. The system proved valuable for the study of the prevention of alloxan cytotoxicity by various carbohydrates and carbohydrate derivatives. D-glucose, 3-O-methyl-D-glucose, D-mannose, 2-deoxy-D-glucose effectively prevented the injury by alloxan. D-Mannoheptulose, D-glucosamine, 1-thio-beta-D-glucose, 5-thio-D-glucose, 2,6-deoxy-D-glucose, D-glyceraldehyde, and dihydroxyacetone had either insignificant or no protective effect.