Novel organic cation transporter 2-mediated carnitine uptake in placental choriocarcinoma (BeWo) cells

Erik Rytting, Kenneth L. Audus

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The placental transport of carnitine is significant because the fetus cannot supply itself with adequate amounts of this nutrient. Carnitine deficiencies in infants can lead to symptoms ranging from muscle weakness to sudden infant death. Objectives of this study include the characterization of novel organic cation transporter 2 (OCTN2) function in the BeWo cell line and the inhibition of placental carnitine uptake by amphetamine derivatives. BeWo cells were seeded in 12- or 24-well tissue culture plates and incubated at 37°C until monolayers were confluent. Uptake studies with radiolabeled L-carnitine and inhibitors in Hanks' balanced salt solution were carried out in the plates at 37°C for 30 min. Uptake of L-carnitine in BeWo cells was Na+-dependent and saturable (Km = 9.8 ± 2.4 μM, Vmax = 800 ± 70 pmol/mg of protein/30 min) with a nonsaturable constant of 2.8 ± 0.3 μl/mg of protein/30 min. Among the amphetamine analogs studied, IC50 values ranged from 2.3 to 9.2 mM, and the inhibition of carnitine uptake was stronger for compounds having a methyl-substituted nitrogen atom. Lineweaver-Burk plots show that inhibition by tetraethylammonium and valproate was competitive; inhibition by ephedrine was not completely competitive. The observed kinetics, Western blot, and inhibition profiles indicate that high-affinity carnitine uptake in the BeWo cell line is mediated by OCTN2. Inhibition of carnitine transport by amphetamines potentially poses serious consequences for fetal development.

Original languageEnglish (US)
Pages (from-to)192-198
Number of pages7
JournalJournal of Pharmacology and Experimental Therapeutics
Volume312
Issue number1
DOIs
StatePublished - Jan 2005
Externally publishedYes

Fingerprint

Choriocarcinoma
Carnitine
Cations
Amphetamine
Amphetamines
Ephedrine
Cell Line
Tetraethylammonium
Sudden Infant Death
Muscle Weakness
Valproic Acid
Fetal Development
Inhibitory Concentration 50
Proteins
Fetus
Nitrogen
Western Blotting
Food

ASJC Scopus subject areas

  • Pharmacology

Cite this

Novel organic cation transporter 2-mediated carnitine uptake in placental choriocarcinoma (BeWo) cells. / Rytting, Erik; Audus, Kenneth L.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 312, No. 1, 01.2005, p. 192-198.

Research output: Contribution to journalArticle

@article{8487e40b113f4da79fe37016d7c2c37d,
title = "Novel organic cation transporter 2-mediated carnitine uptake in placental choriocarcinoma (BeWo) cells",
abstract = "The placental transport of carnitine is significant because the fetus cannot supply itself with adequate amounts of this nutrient. Carnitine deficiencies in infants can lead to symptoms ranging from muscle weakness to sudden infant death. Objectives of this study include the characterization of novel organic cation transporter 2 (OCTN2) function in the BeWo cell line and the inhibition of placental carnitine uptake by amphetamine derivatives. BeWo cells were seeded in 12- or 24-well tissue culture plates and incubated at 37°C until monolayers were confluent. Uptake studies with radiolabeled L-carnitine and inhibitors in Hanks' balanced salt solution were carried out in the plates at 37°C for 30 min. Uptake of L-carnitine in BeWo cells was Na+-dependent and saturable (Km = 9.8 ± 2.4 μM, Vmax = 800 ± 70 pmol/mg of protein/30 min) with a nonsaturable constant of 2.8 ± 0.3 μl/mg of protein/30 min. Among the amphetamine analogs studied, IC50 values ranged from 2.3 to 9.2 mM, and the inhibition of carnitine uptake was stronger for compounds having a methyl-substituted nitrogen atom. Lineweaver-Burk plots show that inhibition by tetraethylammonium and valproate was competitive; inhibition by ephedrine was not completely competitive. The observed kinetics, Western blot, and inhibition profiles indicate that high-affinity carnitine uptake in the BeWo cell line is mediated by OCTN2. Inhibition of carnitine transport by amphetamines potentially poses serious consequences for fetal development.",
author = "Erik Rytting and Audus, {Kenneth L.}",
year = "2005",
month = "1",
doi = "10.1124/jpet.104.072363",
language = "English (US)",
volume = "312",
pages = "192--198",
journal = "Journal of Pharmacology and Experimental Therapeutics",
issn = "0022-3565",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "1",

}

TY - JOUR

T1 - Novel organic cation transporter 2-mediated carnitine uptake in placental choriocarcinoma (BeWo) cells

AU - Rytting, Erik

AU - Audus, Kenneth L.

PY - 2005/1

Y1 - 2005/1

N2 - The placental transport of carnitine is significant because the fetus cannot supply itself with adequate amounts of this nutrient. Carnitine deficiencies in infants can lead to symptoms ranging from muscle weakness to sudden infant death. Objectives of this study include the characterization of novel organic cation transporter 2 (OCTN2) function in the BeWo cell line and the inhibition of placental carnitine uptake by amphetamine derivatives. BeWo cells were seeded in 12- or 24-well tissue culture plates and incubated at 37°C until monolayers were confluent. Uptake studies with radiolabeled L-carnitine and inhibitors in Hanks' balanced salt solution were carried out in the plates at 37°C for 30 min. Uptake of L-carnitine in BeWo cells was Na+-dependent and saturable (Km = 9.8 ± 2.4 μM, Vmax = 800 ± 70 pmol/mg of protein/30 min) with a nonsaturable constant of 2.8 ± 0.3 μl/mg of protein/30 min. Among the amphetamine analogs studied, IC50 values ranged from 2.3 to 9.2 mM, and the inhibition of carnitine uptake was stronger for compounds having a methyl-substituted nitrogen atom. Lineweaver-Burk plots show that inhibition by tetraethylammonium and valproate was competitive; inhibition by ephedrine was not completely competitive. The observed kinetics, Western blot, and inhibition profiles indicate that high-affinity carnitine uptake in the BeWo cell line is mediated by OCTN2. Inhibition of carnitine transport by amphetamines potentially poses serious consequences for fetal development.

AB - The placental transport of carnitine is significant because the fetus cannot supply itself with adequate amounts of this nutrient. Carnitine deficiencies in infants can lead to symptoms ranging from muscle weakness to sudden infant death. Objectives of this study include the characterization of novel organic cation transporter 2 (OCTN2) function in the BeWo cell line and the inhibition of placental carnitine uptake by amphetamine derivatives. BeWo cells were seeded in 12- or 24-well tissue culture plates and incubated at 37°C until monolayers were confluent. Uptake studies with radiolabeled L-carnitine and inhibitors in Hanks' balanced salt solution were carried out in the plates at 37°C for 30 min. Uptake of L-carnitine in BeWo cells was Na+-dependent and saturable (Km = 9.8 ± 2.4 μM, Vmax = 800 ± 70 pmol/mg of protein/30 min) with a nonsaturable constant of 2.8 ± 0.3 μl/mg of protein/30 min. Among the amphetamine analogs studied, IC50 values ranged from 2.3 to 9.2 mM, and the inhibition of carnitine uptake was stronger for compounds having a methyl-substituted nitrogen atom. Lineweaver-Burk plots show that inhibition by tetraethylammonium and valproate was competitive; inhibition by ephedrine was not completely competitive. The observed kinetics, Western blot, and inhibition profiles indicate that high-affinity carnitine uptake in the BeWo cell line is mediated by OCTN2. Inhibition of carnitine transport by amphetamines potentially poses serious consequences for fetal development.

UR - http://www.scopus.com/inward/record.url?scp=11844273267&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=11844273267&partnerID=8YFLogxK

U2 - 10.1124/jpet.104.072363

DO - 10.1124/jpet.104.072363

M3 - Article

C2 - 15316089

AN - SCOPUS:11844273267

VL - 312

SP - 192

EP - 198

JO - Journal of Pharmacology and Experimental Therapeutics

JF - Journal of Pharmacology and Experimental Therapeutics

SN - 0022-3565

IS - 1

ER -