The Mechanism of the Osmotic Adjustment of Body Cells as Determined IN VIVO BY THE VOLUME OF DISTRIBUTION OF A LARGE WATER LOAD Alexander Leaf, … , Oliver Wrong, Elbert P. Tuttle Jr. J Clin Invest. 1954;33(9):1261-1268. https://doi.org/10.1172/JCI103001. Research Article Find the latest version: https://jci.me/103001/pdf THE MECHANISM OF THE OSMOTIC ADJUSTMENT OF BODY CELLS AS DETERMINED IN VIVO BY THE VOLUME OF DISTRIBUTION OF A LARGE WATER LOAD' By ALEXANDER LEAF,2 JACQUES Y. CHATILLON, OLIVER WRONG, AND ELBERT P. TUTTLE, Ja.8 (From the Departments of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Mass.) (Submitted for publication April 5, 1954; accepted May 14, 1954) Since permeability of cell membranes to water tained. A water load of 100 ml. per kilogram of body has been clearly demonstrated, there are several weight was then administered intravenously at a rate of of cells to dilution approximately 20 ml. per minute. The water load was theoretically possible responses given as a 23h per cent solution of dextrose, or dextrose of the extracellular fluid. Osmotic equilibrium and fructose. Blood samples were obtained following the might result from net movement of water into cells infusion at intervals of three to sixty minutes for five in response to extracellular dilution. On the other or six hours in three experiments. In the other experi- hand, net movement of water into cells might be ments blood samples were taken 4 to 6 hours after the infusion was completed. Some of the dogs received 0.3 averted by: 1) active transport of water out of mgm. of atropine and 50 mgm. of Dramamine® to pre- cells preventing a change in intracellular osmotic vent vomiting and salivation. activity; 2) reduction of intracellular osmotic ac- A second series of ten experiments was performed on tivity by means of either osmotic inactivation of dogs either nephrectomized or with ureters ligated. The intracellular solutes or their extrusion from the operation was done under local procaine infiltration (10 to 20 ml. of 1 per cent solution) in two animals and in cells. the remainder under general anesthesia induced and main- These possibilities were tested by determining tained throughout the experiment by the intravenous ad- the volume of distribution of a large water load ministration of 25 to 30 mgm. of sodium pentobarbital which depends on movement of water through the per kilogram of body weight. Immediately following op- body. The data are compared with the total body eration a blood sample for the natural abundance of deu- the dilution of a tracer terium was drawn, and 1 to 2 grams of deuterium oxide water content measured by per kilogram of body weight were given intravenously. amount of deuterium oxide which is independent Blood was drawn one and one-half and two hours later of net movement of water. In the dog the volume for determination of deuterium and as control samples of distribution of a large water load was found to before dilution. Dramamine® and atropine were adminis- approximate closely the total body water content. tered as above. One hundred and thirty-two ml. per kilogram of body weight of a 2.5 per cent solution of fruc- tose and/or glucose were administered intravenously at METHODS AND PROCEDURE a rate of 30 ml. per minute. This quantity of water was chosen to increase the degree of dilution and thus to mini- A. Protocol mize the effects of the errors of measurement on the cal- Fifteen initial experiments were performed in nine un- culated results. The two final blood samples were ob- anesthetized dogs. Two and one-half to five units of tained between 23 and 3Y2 hours after the infusion was Pitressin Tannate in Oil®'4 were given two to sixteen completed. The ureteral ligatures were removed from hours before the experiment to reduce the urinary loss of four dogs, all of which recovered uneventfully. In one water. After the bladder was emptied by catheterization, of these the experiment was later repeated. the animal was weighed and a control blood sample ob- B. Analytical methods 'This study was supported in part by grants from the Plasma sodium and potassium concentrations were Milton Fund of Harvard University, the American Heart measured by flame photometry (1). Total solute concen- Association, and the Greater Boston Chapter of the tration of plasma was determined by the freezing point Massachusetts Heart Association. depression measured with a thermistor.5 Deuterium con- 2Howard R. Hughes Fellow in Medicine. centrations were measured by mass spectrometry (2). 8 Postdoctorate Fellow in Medicine, National Heart Institute, U. S. Public Health Service. 5 The apparatus was developed and constructed for us 'Kindly provided by Dr. A. C. Bratton, Jr., Parke, by Fiske Associates, Inc., 44 Bromfield Street, Boston, Davis and Company, Detroit, Michigan. Mass. 1261 1262 A. LEAF, J. Y. CHATILLON, 0. WRONG, AND E. P. TUTTLE, JR. Urea was determined by the microdiffusion technique of TABLE I Conway (3); glucose by the method of Nelson modified The mean volume of distribution of an intravenous by Somogyi (4); fructose by the method of Rolf, Surt- water load in 15 experiments shin, and White (5); chloride by the method of Wilson and Ball (6). Plasma water was measured gravi- Mean VN,. = 65.6% of Body Weight metrically after drying at 950 to 105° C. to constant Mean Vs01 = 63.6% of Body Weight weight. Data were analyzed by conventional statistical Mean Difference = 1.9% of Body Weight methods (7). Standard Deviation = 2.3% of Body Weight (of Mean Difference) C. Calculations and analytical error to = 0.86 In the calculations of the last ten experiments the values p = 0.4 for sodium, total solutes and deuterium are the averages of repeated determinations made on two separate plasma samples obtained at short intervals, as described above. Analysis of variance reveals no significant differ- The errors of the methods were estimated by the analysis ence between the mean volumes of distribution of of variance of these repeated determinations. The co- the water load calculated from changes in concen- efficient of variation for a single determination of plasma sodium concentration was 0.95 per cent; of total solute tration of plasma sodium (VNa) and total solute concentration, 0.75 per cent; and of deuterium, 1.55 per (Vs.,), but the standard deviation for the differ- cent. As all analyses were done at least in quadruplicate ences between VN5 and Vi01 in individual experi- the estimate of the analytical error for the averages used ments was large (8.9 per cent body weight). The in the calculations was reduced to one-half or less of the results approximate the expected value for total above figures for single determinations. The volume of distribution of the water load was cal- body water in the dog. culated by the following general equation: Because of the considerable discrepancy be- tween VNa and Vsi in individual experiments, ten (G 1) v= C2W-C2W further studies were done. To reduce errors re- sulting from renal losses of water and solutes, V = volume' of distribution of the water load. Cl and C2 = initial and final plasma concentrations of either the dogs were nephrectomized or their sodium or total solutes. ureters were ligated immediately prior to the W = volume of water administered. experiment. Total body water content was calculated as follows: Figure 1 shows the effects of a water load on (I VDO = 2WDO ( -F) the total solute, sodium, glucose and urea concen- trations of plasma in a nephrectomized dog. VDO - deuterium space (total body water content). WD,O = weight of deuterium oxide administered. Equilibrium of distribution of the water load oc- F = atoms per cent excess of deuterium in plasma at curred within two hours. The plasma urea con- equilibrium. centration slowly increased during the study as The volumes, as calculated, had a minimum standard might be expected in a nephrectomized animal. deviation attributable to propagation of the errors of The plasma glucose concentration was still ele- measurements alone (8) estimated to be: 1.4 to 2.4 per vated above the control levels at the end of the cent of body weight for the sodium calculations, 1.6 to 3.0 experiment. per cent of body weight for total solute calculations, and approximately 0.5 per cent of body weight for the deu- The data for the last ten experiments are pre- terium space. sented in Table II. The quantity of water adminis- tered was chosen to cause a large dilution of the RESULTS body fluids with minimal toxic effects. The se- The results obtained in the initial fifteen ex- rum sodium concentrations after the water load periments performed in nine dogs are briefly sum- are in a range not uncommonly seen clinically. marized in Table I. These results were calcu- In eight experiments there occurred a slight rise lated according to Equation 1 with no attempt to in plasma urea concentration in spite of the dilu- correct the data for the small renal losses of water tion. This accumulation of urea is attributable to and solute that occurred during the experiments. the suppression of renal function. In all experi- ° No distinction has been made between liters and kilo- ments the blood glucose level was still elevated at grams of water. the time the last blood samples were drawn. This MECHANISMS OF OSMOTIC ADJUSTMENT OF BODY CELLS IN VIVO 1263 DOG SW ANESTHETIZEDANEPRETOMIZED AOWL WT. 14.79 KG. TOTAL SOLUTE I z 0 160- 140 120. 100 80. 60- 40- GLUC)OSE 20. TIME IN HOURS FIG. 1. CHANGES IN TOTAL SOLUTE, SODIUM, GLUCOSE AND UREA CONCENTRATIONS IN PLASMA FOLLOWING THE INTRAVENOUS ADMINISTRATION OF A LARGE WATER LOAD TO A NEPHEECTOMIZED DOG It is evident that the plasma concentrations of sodium and total solutes had achieved constant values by 21 hours following termination of the infusion.