EFFECT OF FLUORIDE ON INTERRELATION BETWEEN GLUCOSE UTILIZATION PH AND CARBOHYDRATE STORAGE IN A SALIVARY SEDIMENT SYSTEM

The effect of low levels of fluoride (2.2 and 4.4 ppm) on the uptake of glucose, increase in stored carbohydrate and decrease in pH in a salivary sediment system following the addition of glucose was examined at three different initial glucose concentrations (0.05, 0.5 and 5 per cent). With 0.5 and 5 per cent glucose, fluoride inhibited both the fall in pH and increase in stored carbohydrate, the inhibition being greater with 4.4 ppm fluoride than with 2.2 ppm fluoride. When the glucose concentration was 0.05 per cent, the fluoride slightly stimulated the fall in pH and had no discernible effect on carbohydrate storage. With 0.05 per cent glucose, the pH did not fall below 5.6 whereas in the mixtures with 0.5 and 5 per cent glucose, the pH fell well below 5.0, supporting the findings of previous workers that fluoride inhibits more effectively at acid than at neutral pH. The similarity in inhibition with fluoride to that observed earlier with high concentrations of glucose, together with the inhibition by fluoride of glucose uptake, indicated that the simultaneous inhibition by fluoride of both the fall in pH and the formation of sediment carbohydrate resulted from fluoride inhibition of glucose transport. © 1969.