Pentose phosphate pathway enzymes and glucose oxidation in fluoride-fed rats

Abstract

The effect of dietary fluoride ingestion (450 ppm F) on the relative importance of the pentose phosphate and Embden- Meyerhof pathways of glucose metabolism was investigated both in liver and in whole animals. In intact rats there was no effect of fluoride on the C-1/C-6 C14O2 excretion ratio following administration of glucose-I-C14 or glucose-6-C14. There was a 47% decrease in the amount of C14O2 metabolized from glucose-I-C14 in the liver of fluoride fed rats. The level of liver glucose 6-phosphate dehydrogenase in fluoride-fed rats was also decreased by approximately 50%. By regulating food intake it was shown that the decrease in enzyme activity in fluoride-fed rats was a consequence of a direct effect of fluoride on the pattern of food intake. Fluroide ingestion decrease food consumption and resulted in a "continual-nibbling" pattern of food intake, which in turn decreased the glucose 6-phosphate dehydrogenase activity.