Inhibition of system A amino acid transport activity by ethanol in BeWo choriocarcinoma cells.

Abstract

Our purpose was to investigate the influence of ethanol on system A amino acid transporter in BeWo cells. BeWo cells were cultured in the absence or presence of ethanol. The function of system A was monitored by the transport of alpha-(methylamino)isobutyric acid. Messenger RNA levels for system A were assessed by Northern analysis. Treatment of BeWo cells with ethanol reduced the activity of system A. The effect was dose and treatment time dependent. The decrease in system A activity was 38% +/- 3% at 0.75% ethanol with a 16-hour treatment time. The activities of several other transporters tested were not affected. The effect on system A activity was associated with a decrease in the maximal velocity of the transport system without affecting the substrate affinity. Ethanol did not alter the messenger RNA levels for system A. Exposure of BeWo cells to ethanol significantly reduces the function of system A. This finding has potential implications that may be relevant to the pathogenesis of the fetal alcohol syndrome.