Carbohydrate utilization in exercising muscle in subtotally nephrectomized rabbits.
Subtotally nephrectomized rabbits were compared with sham-operated controls. The isolated soleus muscle of one leg was exercised using controlled stimulus parameters at 1 Hz until the contraction tension (amplitude) was reduced by one half. The muscle was then quickly frozen in liquid nitrogen and analyzed for lactate, pyruvate, glycogen, alanine, glutamine and alpha-ketoglutarate. The resting leg was used as a control and similarly frozen and analyzed. The difference between resting and exercised muscle lactate and pyruvate concentration was significantly greater in experimental animals while muscle alanine and alpha-ketoglutarate concentrations were lower in the experimental animals. There was no difference in the time required to reach one half of the muscle contraction amplitude between experimental and control animals. Blood lactate levels rose in the experimental animals to a greater degree than in control animals, similar to that seen in human subjects with renal failure.