Edelman and Leibman (1959) review the methods by which total body water has been measured. The commonest have been measurement of the dilution volume of injected deuterium oxide or antipyrine. In man, the dilution volume of D2O or antipyrine is about 600 ml/kg body weight, but this value is not much use because it will obviously vary with differences in body fat of individuals. Also in dogs, body water is stated as about 60% of body weight (Edelman, 1952). Measurements of D2O space have only limited accuracy and are inadequate to study effectively changes in body water in normal life. Often the best indication of change in body water is change in weight; water is 6 0% of the body weight and changes much more rapidly than the solids of the body. With a diet on which the animal maintains body weight, fluctuations in the metabolism of a dog are not likely to cause change in body fat by more than 20– 30 g/day; greater changes between body weight on one day and the next must be due to changes in body water. In the experiments on water balance described below body weight is often cited as evidence of change in body water.
KeywordsWater Intake Water Exchange Urine Volume Total Body Water Stomach Tube
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