Related Experiment Video
Updated: Jun 13, 2026

Assessment of Glutamine as a Fuel Source for Alveolar Macrophages Exposed to Chronic Ethanol Using an Extracellular Flux Bioanalyzer
Published on: November 15, 2024
Chronic alcohol consumption and intestinal thiamin absorption: effects on physiological and molecular parameters of
Sandeep B Subramanya1, Veedamali S Subramanian, Hamid M Said
1Department of Medical Research, VA Medical Center, Long Beach, and Department of Medicine, University of California College of Medicine, Irvine, California, USA.
Abstract:
Thiamin is essential for normal cellular functions, and its deficiency leads to a variety of clinical abnormalities. Humans and other mammals obtain the vitamin via intestinal absorption. The intestine is exposed to two sources of thiamin, a dietary and a bacterial (i.e., normal microflora of the large intestine) source. Chronic alcohol consumption is associated with thiamin deficiency, which is caused (in part) by inhibition in intestinal thiamin absorption. However, little is known about the physiological and molecular aspects of the intestinal thiamin uptake process that are affected by chronic alcohol use. To address these issues, we used rats fed an alcohol-liquid diet and human intestinal epithelial HuTu-80 cells chronically exposed to ethanol as model systems. The results showed that chronic alcohol feeding to rats led to a significant inhibition in carrier-mediated thiamin transport across both the jejunal brush-border membrane and basolateral membrane domains. This was associated with a significant reduction in level of expression of thiamin transporter-1 (THTR-1), but not THTR-2, at the protein and mRNA levels. Level of expression of the heterogenous nuclear RNA of THTR-1 in the intestine of alcohol-fed rats was also decreased compared with their pair-fed controls. Chronic alcohol feeding also caused a significant inhibition in carrier-mediated thiamin uptake in rat colon. Studies with HuTu-80 cells chronically exposed to ethanol also showed a significant inhibition in carrier-mediated thiamin uptake. This inhibition was associated with a reduction in level of expression of human THTR-1 and THTR-2 at the protein, mRNA, and transcriptional (promoter activity) levels. These studies demonstrate that chronic alcohol feeding inhibits intestinal thiamin absorption via inhibition of the individual membrane transport event across the polarized absorptive epithelial cells. Furthermore, the inhibition is, at least in part, mediated via transcriptional mechanism(s).
Related Concept Videos
Factors Influencing Drug Absorption: Disease States and Pharmacology
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
Drug Absorption: Factors Affecting GI Absorption
In...
Chronic Pancreatitis II: Pathophysiology
Factors Influencing Drug Absorption: Anatomical Parameters
Effect of Hepatic Disease on Pharmacokinetics: Pathophysiologic Assessment and Liver Function Test
Glucose Absorption Into the Small Intestine
