Thyroid hormone regulates the activity and expression of the peptide transporter PEPT1 in Caco-2 cells.

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Ashida K, Katsura T, Motohashi H, Saito H, Inui K

Thyroid hormone regulates the activity and expression of the peptide transporter PEPT1 in Caco-2 cells.

Am J Physiol Gastrointest Liver Physiol. 2002 Apr;282(4):G617-23.

PubMed ID

11897620 [ View in PubMed

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Abstract

An oligopeptide transporter (PEPT1) in the small intestine plays an important role in the absorption of small peptides and peptide-like drugs. We examined the effect of thyroid hormone 3,5,3'-L-triiodothyronine (T(3)) on the activity and expression of PEPT1 in human intestinal Caco-2 cells. Treatment of Caco-2 cells with T(3) inhibited [(14)C]glycylsarcosine uptake in a time- and dose-dependent manner. [(14)C]glycylsarcosine uptake was reduced by pretreatment of the cells with 100 nM T(3) for 4 days (67% of control value), whereas methyl-alpha-D-[U-(14)C]glucopyranoside and [(3)H]threonine uptake were not decreased. Kinetic analysis showed that T(3) treatment significantly decreased the maximum uptake (V(max)) value for [(14)C]glycylsarcosine uptake but had no effect on the K(m) value. Moreover, T(3) treatment caused a significant decrease in the amount of PEPT1 mRNA (25% of the control). Western blotting indicated that the amount of PEPT1 protein in the apical membrane was decreased (70% of the control). These findings indicate that T(3) treatment inhibits the uptake of [(14)C]glycylsarcosine by decreasing the transcription and/or stability of PEPT1 mRNA.

DrugBank Data that Cites this Article

Drug Transporters

Drug	Transporter	Kind	Organism	Pharmacological Action	Actions
Liothyronine	P-glycoprotein 1	Protein	Humans	Unknown	Inducer	Details
Liotrix	P-glycoprotein 1	Protein	Humans	Unknown	Inducer	Details