THE CONCENTRATION OF ELECTROLYTES IN NORMAL HUMAN SALIVA

Abstract

Parotid saliva was collected into graduated tubes by fitting small cups over the parotid papillae. The sodium, chloride, and bicarbonate concentrations and the pH of parotid saliva increased with increasing rates of secretion, but the potassium and phosphate concentrations remained constant at secretion rates greater than 0.5 ml. per minute. Although the latter two ions were always at concentrations higher than serum levels, the parotid juice was always hypotonic but decreasingly so as the rate of flow increased. There was appreciable variation between individuals and also in the same subject from time to time. No difference was noted between the two gustatory stimuli used, dilute acetic acid and glucose candy. The potassium concentration in parotid saliva was higher than in mixed submaxillary and sublingual saliva. Continuous recording of the rate of secretion on a smoked drum showed cyclic variations from minute to minute, indicating that timed collections over a period of minutes give mean rather than actual rates of flow.