Serine racemase and D-serine transport in human placenta and evidence for a transplacental gradient for D-serine in humans.

Objective: To investigate the possible role of human placenta in providing D-serine to the developing fetus.

Methods: Expression of serine racemase in placenta was determined by reverse transcriptase polymerase chain reaction and northern analysis and confirmed by subsequent cloning. The transport of D-serine by human ATB(0) was characterized by expressing the cloned cDNA transiently in mammalian cells using the vaccinia virus expression system.

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

Objective: Our purpose was to investigate the influence of ethanol on system A amino acid transporter in BeWo cells.

Study Design: 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.