[Relationship of diet, biomass and expression of diabetes in eSS rats]

The long-term effect of feeding eSS rats three commercial diets on the development of diabetes and its complications has been investigated. These diets differ in their proportions of carbohydrates, fibres, lipids and proteins: diet A is rich in lipids, B in carbohydrates and fibres and C in proteins. However, the proportions of these components lie within the range recommended for rats. Animals receiving diet C showed the highest growth rate and were the first to develop diabetes at the age of four months. They had, moreover, the highest levels of triglycerides, total cholesterol and HDL-cholesterol. Animals fed the A diet were heavier than the other groups at 13 months of age, showing a diabetic glucose tolerance test and the highest values of circulating insulin. They were already diabetic when tested at the age of 6 months. The group fed the B diet remained leaner than the other groups and free of diabetes up to the test performed when they were ten months old. The findings at the age of 23 months were: the A animals developed the largest retroperitoneal and epididymal adipose tissue masses, the C group was the most affected by cataracts which were total, and bilateral in some cases, whereas the B rats were free of them and the A animals showed milder lesions than the C rats. Histological studies of pancreas and kidneys demonstrated that the C animals had fewer Langerhans islands than the other groups and the most severe renal lesions while the B animals had no renal damage. It is concluded that diets leading to overweight, particularly those rich in proteins, make the diabetic syndrome worse in eSS rats.