Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2008
Publication Date: 5/1/2008
Citation: Nichols, B.L., Quezada-Calvillo, R., Ao, Z., Hamaker, B.R., Marini, J., Jahoor, F. 2008. Contribution of mucosal maltase-glucoamylase to mouse small intestinal starch alpha-glucogenesis and total glucose metabolism[abstract]. Journal of Federation of American Societies for Experimental Biology. 22:686.2 Interpretive Summary:
Technical Abstract: Digestion of starch requires four mucosal maltases; sucrase and isomaltase (Si) and maltase and glucoamylase (Mgam). We ablated Mgam to study its roles. The in vitro effect was a slowing of null mucosal activity to 10% of WT. Here we report in vivo effects of Mgam KO on mouse glucose metabolism. alpha-Glucogenesis was assayed by digestion of IG 13C-starch to blood 13C-glucose. UL13C-starch (Sigma: M+6) was predigested with amylase (Sigma) to 13C-limit dextrin (LD), which contained 3.48 +/- 0.12 g/L glucose equivalents. 13C-LD was infused IG. D-Glucose-C-d7 (Isotec: M+7) was infused IV (7.5 g/L) to measure total glucose flux. Mice were fasted overnight and tail vein and gastric cannulas inserted. Both IG snd IV were infused at 0.0001 L/h. 4 h blood was collected from submandibular sinus. Total glucose was measured by analyzer and glucose isotopomers as penta-acetate derivatives by PCI-GC/MS. Baseline bloods were from uninfused mice. The null has only 60% of WT alpha-glucogenesis. Because of increased null gluconeogenesis, total glucose metabolism in Mgam null mice was identical to WT.