RELATIONSHIPS BETWEEN DIET CONTROL AND THE DEVELOPMENT OF SPONTANEOUSTYPE-II DIABETES AND DIABETIC NEPHROPATHY IN OLETF RATS

The effect of a 30% restricted diet on the development of diabetes and diabetic nephropathy was examined using the Otsuka Long Evans Tokushi ma Fatty (OLETF) rat which develops non-insulin-dependent diabetes mel litus (NIDDM) spontaneously after 25-30 weeks of age. The first experi mental group that received 30% restricted feeding from six to 80 weeks old, showed complete suppression of spontaneous diabetes up to 40 wee ks of age and showed milder histopathological change of pancreatic isl ets, than those of the control group. The second group which received 30% restricted feeding during 30-80 weeks, showed a gradual decrease i n clinical diabetes with age, even though they had already developed d iabetes at 25 weeks. In both groups, levels of urinary protein content appeared to decrease, compared with that in control rats, although a gradual increase of urinary protein was observed with age. Histopathol ogically, glomerular damages were slight to mild in both groups. Howev er, no improvement in nephrotic complication was observed for the grou p which received a 30% restricted feeding after 70 weeks of age. These results clearly show that the balanced-control diet, given at a 30% r estricted feeding level and at an early phase, is effective in the pre vention or improvement of NIDDM and nephrotic complications. Diet ther apy after 70 weeks of age, however, had little or no effect.