Lack of diabetogenic effect of alloxan in protein-calorie malnourished rats.

Male weanling rats were fed one of three diets for 46 days. The diets were control, a 4% casein-containing and a 4% casein + 0.7% cysteine diets. On day 47, the rats were injected with alloxan (40 mg/kg body weight) via the tail vein and frequencies of alloxan-induced diabetes were appraised on days 55-57 by measurement of blood glucose, urine output, water intake and food intake. Alloxan was almost ineffective in producing diabetes in the two low-protein groups (frequencies of diabetes = 0/11 and 3/11 for the 4% casein diets without and with cysteine, respectively) but was highly effective in the control group (100% diabetogenesis). The decreased diabetogenicity of low-protein diets was not due to decreased food intake. All the animals fed control diet in amounts which matched the intake of protein-malnourished animals became diabetic when alloxan was administered. These data suggest a defect in the alloxan-glucose recognition site on beta cells of protein malnourished rats.