CHEMICAL AND PATHOLOGICAL CHANGES IN DIETARY CHLORIDE DEFICIENCY IN THE RAT

Abstract

Only in recent years has it been demonstrated unequivocally that elimination of chloride from the diet leads to an impairment of health.The authors reported in a previous paper (1) that chloride deficiency (0.012 per cent Cl in the diet) caused a reduction in the growth rate, a reduction in blood chloride, an increased blood bicarbonate, and almost a cessation of the urinary excretion of chloride.Growth and the energy and protein metabolism in chloride deprivation were studied by Voris and Thacker (2) on pair-fed rats maintained on a diet containing 0.02 per cent chloride.The rats on the deficient diet showed a loss of appetite but an increased water consumption.The deficient rats gained less water (as per cent of total fat-free gain) and less fat than the controls.The ratio of water gained to protein gained was lowered, leading the authors to characterize the tissue cells as water-poor.More of the energy of the ingested food was lost as heat and less stored in the chloride-low rats than in the controls.The deficient animals gained more protein in terms of per cent of gain in body weight but gained less in per cent of total body protein.This was reflected by an increase in the output of urinary nitrogen and a decrease in nitrogen retention.The deficient animals showed a greater gain, proportionately, of residual (mainly inorganic) substance.The effect of the chloride deficiency on the mineral composition of the body was more closely analyzed by Thacker (3) on the above rats.He found that there was a decrease in the content of chloride, sodium, and potassium, and an increase in the content of calcium, magnesium, and phosphorus, presumably because the ratio of soft tissue to skeleton is lowered.The concentrations of chloride, sodium, and potassium were also decreased with respect to the water content and to the water gained, but without disturbing the ratio of sodium to potassium.There was a decrease in the retention of all the above mineral elements except chloride.The present investigation was undertaken to obtain more of an insight into the nature of the physiological disturbances caused by deficiency of chloride.Estimations of the extracellular phase were made from the chloride composition and from the distribution of the radioactive isotope, Na22, in view of the apparent alteration in water metabolism and because 83