Body composition in a rat model of moderate uremia.

To evaluate whether abnormal body composition in uremia is a consequence of undernutrition from poor food intake, body fluid compartments and individual organs were measured in moderately uremic (5/6th nephrectomy) and pair fed control rats and in a second group of moderately uremic and control rats on two levels of dietary protein: 43% (HP) and 18.5% (LP). Uremic rats in both groups had significantly increased total body water (TBW) and extracellular water (ECW) and decreased total body solids (TBS). Heart weight in uremic rats was significantly increased, whereas weight of muscle, brain, adrenal, and fat free liver, as a percent of body weight, did not differ from control rats. There were no differences between uremic rats on HP and LP diets in TBW, ECW, TBS or in heart weight and muscle weight. Uremic rats on HP had increased kidney and liver weights. These data demonstrate abnormal body composition in a rat model of moderate uremia. Changes observed appear to be primarily a consequence of uremia per se rather than of undernutrition or level of dietary protein.