WATER METABOLIC PARAMETER CHANGES IN RHESUS-MONKEYS DURING EXPOSURE TO PROLONGED RESTRICTION OF MOTOR-ACTIVITY

The objective of this investigation was to determine the effect of pro longed restriction of motor activity (hypokinesia [HK]) on several par ameters of water metabolism in primates. The studies were per formed o n 12 rhesus monkeys aged 4-5 yr (5.10-6.85 kg) during the hypokinetic period of 90 d and during the prehypokinetic period of 30 d. They were divided into two equal groups: the first group was placed under ordin ary vivarium conditions (vivarium control animals) and the second grou p was subjected to 90 d of HK (hypokinetic animals). For the simulatio n of the hypokinetic effect, the primates were immobilized on their ab domens in special tables. The legs of the monkeys were immobilized wit h hip and knee joints extended. The primates retained freedom of movem ent at elbow, wrist, and ankle. During the preexperimental period of 3 0 d and during the experimental period of 90 d, the following variable s were determined: body weight, total body fluid content, specific tot al body fluid, mean fluid consumed and eliminated in urine, specific p lasma resistance, hematocrit level, and plasma concentrations of sodiu m (Na) and potassium (K). In the hypokinetic primates, body weight dec reased significantly when compared to the controls. Mean fluid intake, total body fluid, and specific total body fluid decreased, whereas me an daily fluid loss and specific mean daily fluid elimination increase d significantly. Specific plasma resistance, hematocrit level, and pla sma electrolyte concentrations increased significantly when compared t o the control primates. It was concluded that prolonged restriction of motor activity induces significant changes in water metabolic paramet ers of primates leading in decreased total water content of the body.