Related Experiment Video

Updated: Oct 7, 2025

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport
08:42

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport

Published on: November 27, 2016

11.3K

Internalization and Decrease of Duodenal DMT1 Involved in Transient Suppression of Iron Uptake in Short-Acting

Anna Arita1,2, Ichiro Kita3, Shoko Shinoda3

  • 1Department of Health Promotion Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan. a-arita@tmu.ac.jp.

Biological Trace Element Research
|January 8, 2022
PubMed

Insights

A small iron dose induces a short-acting mucosal block (SAMB) in rats by reducing duodenal divalent metal transporter 1 (DMT1) protein levels. This mechanism transiently suppresses iron absorption without altering gene expression.

Area of Science:

  • Physiology
  • Nutritional Science
  • Gastroenterology

Background:

  • Oral iron administration can induce a mucosal block (MB), suppressing intestinal iron absorption.
  • A recently identified short-acting mucosal block (SAMB) involves transient iron uptake suppression without gene changes, specific to iron-deficient rats.
  • The roles of nonheme iron transporters, divalent metal transporter 1 (DMT1) and ferroportin (FPN), in SAMB remain unclear.

Purpose of the Study:

  • To investigate the involvement of DMT1 and FPN in the transient suppression of iron uptake during SAMB.
  • To elucidate the molecular mechanisms underlying SAMB in iron-deficient rats.

Main Methods:

  • SAMB was induced by infusing 1 mg of iron into the duodenal loop of iron-sufficient and iron-deficient rats.
  • Duodenal tissue was analyzed for DMT1 and FPN expression and intracellular distribution using fluorescence intensity and puncta imaging.
  • Changes in DMT1-IRE protein levels and localization were assessed at 15 and 60 minutes post-iron loading.

Main Results:

  • Iron deficiency increased total duodenal DMT1 and DMT1-IRE expression.
  • Following 1 mg iron loading, duodenal DMT1 fluorescence intensity decreased in iron-deficient rats to levels similar to iron-sufficient rats.
  • Internalization of DMT1-IRE into puncta increased significantly at 60 minutes post-iron loading; FPN intracellular distribution was unaffected.

Conclusions:

  • The decrease and internalization of DMT1-IRE protein are likely involved in the iron uptake suppression observed in SAMB.
  • SAMB represents a rapid, post-transcriptional regulatory mechanism for intestinal iron absorption.
  • These findings highlight DMT1's dynamic regulation in response to luminal iron availability.
Keywords:
DMT1FPNIronMucosal blockShort-acting mucosal block

More Related Videos

Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease06:04

Ex Vivo Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease

Published on: February 9, 2016

21.5K
Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D11:27

Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D

Published on: March 16, 2017

16.5K

Related Concept Videos

Drug Absorption: Factors Affecting GI Absorption01:19

Drug Absorption: Factors Affecting GI Absorption

The process of oral drug absorption can be influenced by several factors. Weakly acidic drugs tend to be absorbed more readily from the stomach due to their nonionized state. However, absorption may be less efficient in the upper intestine, where drugs are often ionized. Interestingly, despite the stomach's apparent advantage for drug absorption, its mucous layer can hinder diffusion. Its surface area is also smaller than the intestine's, which can further slow down the absorption rate.
5.0K
Factors Influencing Drug Absorption: Anatomical Parameters01:23

Factors Influencing Drug Absorption: Anatomical Parameters

Drug absorption involves the movement of drugs from the point of administration into the systemic circulation. Initially, Gastrointestinal (GI) motility propels the drug through the digestive tract and into the stomach. However, the stomach's high acidity and limited surface area restrict its role in drug absorption for most drugs. The drug then moves from the stomach to the small intestine via gastric emptying, which can be slowed by various factors, including interactions with other...
316
Factors Influencing Drug Absorption: Disease States and Pharmacology01:25

Factors Influencing Drug Absorption: Disease States and Pharmacology

Multiple disease states can significantly influence the oral drug absorption process by affecting blood flow and the functionality of the gastrointestinal (GI) system. Various GI diseases, including conditions that alter GI motility, such as diarrhea, decreased acid secretions (achlorhydria), and infections, have been associated with reduced drug absorption.
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
910
The Early Endosome: Endocytosis of Transferrin01:28

The Early Endosome: Endocytosis of Transferrin

Essential proteins such as insulin or low-density lipoprotein (LDL) and micronutrients such as iron enter a eukaryotic cell through receptor-mediated endocytosis. Subsequently, the early endosomes fuse with the vesicles containing such receptor-ligand complexes and play a vital role in sorting the incoming ligands and receptors. While the ligands are either degraded inside the vesicle or released into the cytosol, their receptors are returned to the plasma membrane for further rounds of...
3.6K
Carrier-Mediated Transport01:06

Carrier-Mediated Transport

Carrier-mediated transport is a pivotal process in drug absorption, particularly for lipid-insoluble drugs, and encompasses facilitated diffusion and active transport. Facilitated diffusion allows drugs to move along their concentration gradient without energy expenditure, while active transport utilizes ATP to drive drug movement against this gradient.
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
587
Glucose Absorption Into the Small Intestine01:26

Glucose Absorption Into the Small Intestine

Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and...
32.8K