|Burrin, Douglas - Doug|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2005
Publication Date: 5/1/2005
Citation: Burrin, D.G., Lambert, B., Stoll, B., Guan, X. 2005. Gastrointestinal gluconeogenesis is absent in the 36hour fasted piglet. Journal of Federation of American Societies for Experimental Biology. 19(4):A-420. Interpretive Summary: Interpretive Summary not needed for this 115.
Technical Abstract: We previously showed that glucose is a major intestinal oxidative fuel in the piglet. However, recent studies in rats indicate that the intestine is an important site of gluconeogenesis (Croset et al., Diabetes, 2001, 50:740). We quantified the gastrointestinal glucose metabolism kinetics in vivo in 28-d-old piglets implanted with catheters in the carotid artery, jugular vein, and portal vein and an ultrasonic flow probe on the portal vein. Piglets were fasted for 36 hours and then received a 4-h constant intravenous infusion of U-13C-glucose (75 µmol x kg-1 x h-1). The arterial and portal venous plasma isotopic enrichments of glucose, lactate and alanine were analyzed by GC-MS. Mean (+/- SEM) fluxes were calculated using the arteriovenous mode. During the 4-h period, there was a significant net uptake of glucose (241.8 +/- 62 µ mol'kg-1'h-1). The mean arterio-venous difference in 13C-glucose enrichment was not significantly different from zero. However, the rate of 13C-glucose uptake was significantly different from zero (23.7 +/- 7.8 micro-mol x kg-1 x h-1), indicating net gastrointestinal utilization of arterial glucose. Of the glucose extracted by the gut, 14.5% and 9.1% was released as lactate and CO2, respectively. We conclude that there is glycolytic and oxidative metabolism of glucose, but no significant gluconeogenesis, by the gastrointestinal tissues in the fasted piglet. (Supported by USDA and NIH)