Abstract
Glucose transport and metabolism by rat small intestine was investigated by using a preparation for the combined perfusion of the lumen and the vascular bed. 2. When 5 mM-glucose was present in the lumen, only 29% was transported unchanged to the vascular side. Lactate output into the vascular and luminal fluids accounted for a further 53% and 4% respectively of the glucose taken up from the lumen. 3. Glucose was readily taken up when added at 5 mM to the vascular compartment only. Vascular lactate output accounted for approx. 33% of the glucose uptake, and luminal lactate for 6%. 4. When 2 mM-glucose was added to the lumen with 5 mM-glucose in the vascular perfusate, there was no detectable net transport of glucose to the vascular side. However, of the glucose taken up from the lumen, 31% and 2% could be accounted for by increases in vascular and luminal lactate respectively. 5. When 10 mM-glucose was added to the lumen, with 5 mM-glucose in the vascular perfusate, 33% of the glucose disappearing from the lumen was transported to the vascular side. Extra lactate output to the vascular and lumen perfusates accounted for 50% and 9% respectively of the glucose uptake from the lumen. 6. These studies indicate that at low luminal glucose concentrations no sugar is transferred to the blood unchanged, and at sugar concentrations of 5--10 mM only 25--50% of the glucose leaving the lumen reaches the serosal side intact. Furthermore, the small intestine has a greater propensity to form lactate from luminal glucose than from vascular glucose.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ATKINSON R. M., PARSONS B. J., SMYTH D. H. The intestinal absorption of glucose. J Physiol. 1957 Mar 11;135(3):581–589. doi: 10.1113/jphysiol.1957.sp005732. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bronk J. R., Ingham P. A. Sugar transfer from the lumen of the rat small intestine to the vascular bed. J Physiol. 1979 Apr;289:99–113. doi: 10.1113/jphysiol.1979.sp012727. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CHAIKOFF I. L., KATZ J., KIYASU J. Y. Nature of the 14C compounds recovered in portal plasma after enteral administration of 14C-glucose. Biochim Biophys Acta. 1956 Aug;21(2):286–290. doi: 10.1016/0006-3002(56)90009-9. [DOI] [PubMed] [Google Scholar]
- Fisher R. B., Gardner M. L. A kinetic approach to the study of absorption of solutes by isolated perfused small intestine. J Physiol. 1974 Aug;241(1):211–234. doi: 10.1113/jphysiol.1974.sp010650. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HESTRIN-LERNER S., SHAPIRO B. Absorption of glucose from the intestine. II. In vivo and perfusion studies. Biochim Biophys Acta. 1954 Jan;13(1):54–60. doi: 10.1016/0006-3002(54)90270-x. [DOI] [PubMed] [Google Scholar]
- Hanson P. J., Parsons D. S. The utilization of glucose and production of lactate by in vitro preparations of rat small intestine: effects of vascular perfusion. J Physiol. 1976 Mar;255(3):775–795. doi: 10.1113/jphysiol.1976.sp011307. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson P. J., Parsons S. Metabolism and transport of glutamine and glucose in vascularly perfused small intestine rat. Biochem J. 1977 Sep 15;166(3):509–519. doi: 10.1042/bj1660509. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LANGDON R. G., TAYLOR W. R. Intestinal absorption of glucose in the rat. Biochim Biophys Acta. 1956 Aug;21(2):384–385. doi: 10.1016/0006-3002(56)90027-0. [DOI] [PubMed] [Google Scholar]
- Leese H. J., Bronk J. R. Automated fluorometric analysis of micromolar quantities of ATP, glucose, and lactic acid. Anal Biochem. 1972 Jan;45(1):211–221. doi: 10.1016/0003-2697(72)90021-8. [DOI] [PubMed] [Google Scholar]
- Pritchard P. J., Porteous J. W. Steady-state metabolism and transport of D-glucose by rat small intestine in vitro. Biochem J. 1977 Apr 15;164(1):1–14. doi: 10.1042/bj1640001a. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TZUR R., SHAPIRO B. Intestinal absorption of galactose. Biochim Biophys Acta. 1960 Aug 12;42:325–333. doi: 10.1016/0006-3002(60)90796-4. [DOI] [PubMed] [Google Scholar]
- Windmueller H. G., Spaeth A. E. Respiratory fuels and nitrogen metabolism in vivo in small intestine of fed rats. Quantitative importance of glutamine, glutamate, and aspartate. J Biol Chem. 1980 Jan 10;255(1):107–112. [PubMed] [Google Scholar]