The occurrence of renal diabetic complications was studied in diabetic nono
bese IIM/FmeSS (eSS) rats. The results were compared with eumetabolic Wista
r rats paired by sex and age. Between 6 and 12 months of age, eSS male rats
had higher fructosamine values and glucose intolerance as well as increasi
ng proteinuria and uremia. Enhancement in water, calcium and phosphorus fra
ctional excretion with a concomitant lower sodium excretion, was observed f
rom 12 months of age on. 18- and 21-month-old eSS rats exhibited fasting hy
perglycaemia and rising values of fructosamine, glucose intolerance and gly
cosuria. Simultaneously, a notorious worsening of proteinuria as well as al
terations in glomerular filtration were verified. Optic microscopy of 12-mo
nth-old eSS rat kidneys showed areas of tubular dilatation with protein cyl
inders. In 21-month-old eSS animals, kidneys appeared overtly damaged. Incr
eased capsular, glomerular and Henle's thin loop diameters were verified in
12- and 21-month-old eSS rats. Glomeruli showed diffuse hypertrophy of mes
angial tissue and thickening of the basement membrane. Areas of markedly at
rophic and dilated tubules containing acidophilic proteinaceous material we
re observed. At age of 21 months, kidneys of eumetabolic Wistar control rat
s presented foci of interstitial and pielic inflammatory infiltrates.