Effective body water half-life and total body water in rhesus and cynomolgus monkeys.

Although body water content and effective water half-life have been determined in several mammalian species, including man, these measurements are not available for sub-human primates to our knowledge. Values were therefore determined in a group of rhesus and cynomolgus monkeys. A fairly wide range of water half-life values was found in each of the two species between animals, but there was little variation within animals who had more than one determination over the course of 1 year. Mean values for effective water half-life were 7.2 days and 3.7 days for naturally menstruating females of the cynomolgus and rhesus species, respectively. Water half-life in female rhesus monkeys with artificial menstrual cycles averaged 6.2 days. Females of both species had a similar percentage of body water content of 64%. Water half-life measured 7.1 and 8.5 days in two male rhesus; and water content was 62% of body weight in one of these animals.