Utilization of Nutrients by Isolated Epithelial Cells of the Rat Colon

Isolated suspensions of co10nocytes from the tat were used to assess utilization, interaction, and fate of metabolic substrates normally obtained from colonie bacteria (acetate, propionate, butyrate) or derived from the blood circulation to the colonic mucosa (D-g1ucose, acetoacetate, L-g1utamine).The short-chain fatty acid n-butyrate (10 mM), on its own, accounted for 86% of the total oxygen consumption and suppressed oxidation of endogenous fuel by 82%.This value was not altered by the addition of acetoacetate (5 mM), of L-g1utamine (5 mM), or of D-g1ucose (10 mM).Activation of shortchain fatty acids by co10nocytes proceeded in the order of butyrate ~ acetate ~ propionate.D-G1ucose on its own accounted for 30% of the oxygen consumption by co10nocytes and hardly suppressed utilization of endogenous fuels.Co10nocytes utilized ketone bodies (acetoacetate) and produced them (acetoacetate and (3-hydroxybutyrate) from shortchain fatty acids.Considering the interaction of substrates, isolated colonic epithelial cells utilized respiratory fuels in the preferential order of butyrate > acetoacetate> glutamine> glucose.The high rate of CO 2 production from butyrate should be a worthwhile means of examining the functional activity of the colonic mucosa clinieally and in vivo.The lining epithelial cells of the gastrointestinal tract, such as enterocytes and colonocytes, renew rapidly and require energy to sustain maturation of cells, absorption of ions, of carbohydrates, of fats, and of amino acids.Enterocytes of the small bowel