Glucose and 3-O-methylglucose protection against alloxan poisoning of pancreatic alpha and beta cells.

Alloxan infused into the isolated perfused rat pancreas caused transient insulin secretion release. Alloxan poisoning also prevented subsequent induction of glucose-mediated unsulin release and also prevented the inhibition of glucagon release by glucose. Glucose or 3-O-methylglucose infused simultaneously with alloxan protected the alpha- and beta-cell, allowing subsequent glucose inhibition of glucagon secretion and stimulation of insulin release. The above alloxan effects were dose-related, the alpha-cell being one fourth as sensitive to alloxan as the beta-cell. The data indicate that (1) alloxan and glucose suppression of amino-acid-stimulated glucagon secretion is independent of concomitant insulin secretion; (2) alloxan, like glucose, affects alpha-and beta-cells directly, stimulating the beta-cell and inhibiting the alpha-cell; and (3) alloxan acts on a glucoreceptor system with comparable physicochemical characteristics common to both cell types.