Diurnal rhythmicity in intestinal SGLT-1 function,Vmax, and mRNA expression topography
- 1 February 2001
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Gastrointestinal and Liver Physiology
- Vol. 280 (2) , G209-G215
- https://doi.org/10.1152/ajpgi.2001.280.2.g209
Abstract
Mechanisms underlying the circadian rhythmicity in intestinal sugar absorption remain unclear. To test whether this rhythmicity is caused by changes in Na+-glucose cotransporter 1 (SGLT-1) function, we measured phloridzin-inhibitable sugar fluxes as an index of SGLT-1 activity. Jejunum obtained from rats killed at 6-h intervals during a 12-h light-dark cycle (CT0 is circadian time 0 h, time of light onset) were mounted in Ussing chambers, and 3- O-methylglucose (3-OMG) fluxes were calculated before and after addition of phloridzin. 3-OMG-induced change in short-circuit current and absorptive flux were significantly greater at CT9 than at CT3. This increase was phloridzin inhibitable. Kinetic studies indicated a significant increase in SGLT-1 maximal velocity ( Vmax) at CT9. Food intake between CT3 and CT9 was max.Keywords
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