1. Cataract formation in streptozotocin-induced diabetes in rats was reduced by approximately 85% when a diet rich in maize oil (300 g/kg diet) (fat diet) was given, thus confirming results of earlier studies. However, the concentration of sorbitol in the lens of diabetic animals remained high, the values for diabetic rats given the standard diet and the fat diet being 65 and 40 μmol/g protein respectively.
2. With the standard diet, the fatty acid profile of the triglycerides of the epididymal fat pads was characterized by a greater relative proportion of saturated fatty acids for the diabetic animals compared to that for the normal animals. The fat diet moderated the tendency towards saturation in the diabetic animals.
3. The fat diet had other effects on the diabetic animals; these included a reduced mortality rate, increased body-weight, a decrease in the daily water intake, and in the daily urinary excretion of glucose and urea.
4. In the diabetic animals the fat diet had no effect on the specific activities in the liver of hexokinase (EC 220.127.116.11), glucokinase (EC 18.104.22.168), phosphofructokinase (EC 22.214.171.124) and pyruvate kinase (EC 126.96.36.199). However, the specific activity of glucose-6-phosphatase (EC 188.8.131.52) was reduced, while that of malate dehydrogenase (decarboxylating) (NADP) (EC 184.108.40.206) was increased. The NAD+: NADH ratio, as calculated from liver pyruvate and lactate concentrations, tended to increase.
5. The results suggested that the fat diet moderated the long-term metabolic effects of diabetes.