The effect of dietary fructose and diabetes on the rat kidney.

To determine whether the fructose moiety of sucrose or the lack of some factor essential for the integrity of the microvascular system is responsible for the development of sucrose-induced glomerulosclerosis, a series of diets with or without such a factor and/or fructose was fed to rats over a 6-month period. Consumption of diets containing or yielding fructose caused a significant increase in kidney weight in comparison with glucose-yielding diets. Diabetic animals also exhibited an increased kidney weight. The incidence of diffuse glomerulosclerosis, tubular damage and lymphocyte infiltration was increased in the starch-diabetic, fructose- and sucrose-normal groups. Diabetic MRC 41B- and normal MRC 41B/fructose-, MRC 41B-, glucose- and starch-fed rats (with the exception of one animal in the latter group) did not develop these kidney lesions. Sucrose-, in comparison with starch-ingestion was found to produce significant increases in blood fructose and kidney fructose-1-phosphate concentration. The results are discussed in relation to blood-glucose concentration, renal-fructose metabolism and the development of glomerular and tubular damage.