Modification of the glomerular basement membrane in sucrose-fed and streptozotocin-diabetic rats

Rats were fed on diets containing either sucrose or starch as the carbohydrate component (55%) for eight months. Diabetes was induced in animals of both groups by injecting streptozotocin (50 mg/kg body weight). Diabetic rats failed to gain weight, had enlarged kidneys, polyuria and elevated blood glucose levels. Starch and sucrose fed rats gained weight normally and had normal blood glucose levels. Sucrose fed rats had enlarged kidneys. Regional thickening of the glomerular basement membrane was present in sucrose-fed and diabetic rats but not in starch-fed controls. Glomerular basement membrane isolated from pooled kidney cortices from rats in the different experimental groups were analysed for amino acid, disaccharide and hexosamine content. Hydroxylysine (9 to 20%), hydroxyproline (21 to 24%), disaccharide (27%) and hexosamine (26%) were increased in membranes insolated from the three experimental groups, compared with starch-fed non-diabetic controls. An increase in low molecular weight components of the glomerular basement membrane of sucrose-fed and diabetic rats was observed using electrophoresis in sodium dodecyl sulphate. Significantly higher (p < 0.001) glucosyltransferase activity was present in kidney supernatants prepared from sucrose-fed (1050 +/- 60 nmol/2h/kidney) compared to starch-fed rats (510 +/- 40 nmol/2h/kidney). Sucrose feeding induces changes similar to those found in diabetes and the induction of diabetes made little difference over the feeding of sucrose alone.