Hydrolysis and absorption of pantothenate and its coenzymes in the rat small intestine.

The transport of pantothenate by the rat small intestine occurs by simple diffusion. There was no significant difference in the rate of pantothenate absorption in the upper, middle or lower sections of the intestine. Coenzyme A was hydrolyzed to pantetheine and pantothenate in the intestinal lumen via the following series of reactions: coenzyme A leads to phosphopantetheine leads to pantetheine leads to pantothenate. Intestinal tissue, which contains high levels of pantetheinase, quickly degrades pantetheine to pantothenate, which is then transported to the blood and thence to other tissues. Tissue distribution patterns of 14C 5 hours after intraluminal administration of 14C-labeled coenzyme A or [14C]pantothenate were similar; approximately 40% of the 14C was present in muscle and 10% in liver.