studies

HEPATOLOGY, VOLUME 62, NUMBER 1 (SUPPL) AASLD ABSTRACTS 857A
inhibition of two ceramide synthetic pathways on hepatic Plin2
expression, steatosis, and glucose and lipid homeostasis in
vivo. In vitro, we investigated the individual effects of de novo
synthetic enzymes on Plin2 regulation. METHODS Mice were
fed a Lieber-DeCarli control or ethanol diet for 4 weeks and
pharmacologically treated i.p. with imipramine (an inhibitor
of sphingomyelinase (SMASE)); myriocin (an inhibitor of serine
palmitoyl transferase (SPT), the rate limiting enzyme of de
novo ceramide synthesis); or saline. Various metabolic parameters,
serum chemistries and glucose tolerance were measured.
Liver samples were taken for immunoblotting, mRNA analysis
and ceramide measurement by mass spectrometry. In vitro, we
incubated VL-17A cells (ethanol-metabolizing human hepatoma
cells) with control or ethanol media and inhibited key enzymes
in the de novo ceramide synthetic pathway with myriocin,
fumonisin B1 (FB-1, an inhibitor of ceramide synthase), or
GT-11 (an inhibitor of dihydroceramide desaturase). Plin2
mRNA and protein, lipids, and markers of translation were
quantified. RESULTS SPT and SMASE inhibition in alcohol-fed
mice reduced hepatic triglycerides (TG) by approximately 37%
(p