Does Phosphorylation Affect Transport of Inorganic Phosphate?

Abstract

1. This study investigated the effects of fructose and 2-deoxyglucose on the uptake and release of phosphate from everted intestinal sacs of mice. 2. Both the sugars significantly decreased the release of phosphate without affecting the uptake. 3. Succinate and fumarate were able to partially reverse the inhibition of phosphate release exerted by fructose but not that exerted by 2-deoxyglucose. 4. Pre-loading with mannoheptulose, a known inhibitor of hexokinase, improved the release of phosphate in the presence of either of these sugars. 5. Adrenaline, known to inhibit phosphorylation of 2-deoxyglucose, reduced the inhibition exerted by this sugar on phosphate release. 6. These results indicate that the inhibition of phosphate release caused by these sugars may be due to the trapping of free phosphate during their metabolism in the gut wall.