Down-regulation of organic anion transporter 2 mRNA expression by nitric oxide in primary cultured rat hepatocytes.
Role of nitric oxide (NO) on the expression of organic anion transporter 2 (OAT2) located in sinusoidal domain of hepatocytes has been investigated. Effect of NO generated in vivo in rat and delivered in vitro to hepatocytes was determined. Lipopolysaccharide (LPS) and spermine NONOate (SPER/NO) were selected as the NO donors for in vivo and in vitro experiments, respectively. Constitutive basal expression of rOAT2 mRNA was detected in the normal rat liver and the level of its expression was decreased by intraperitoneal administration of LPS. This LPS-induced decrement did not occur when aminoguanidine (AG), an inhibitor of iNOS, was co-administered with LPS. The expression of rOAT2 mRNA was detected in hepatocytes, but not in the nonparenchymal cells. In the primary cultured hepatocytes obtained from normal rats (normal hepatocytes), a time-dependent decline of rOAT2 mRNA expression was observed, but not in the hepatocytes obtained from rats pretreated with gadolinium chloride (GdCl3, Gd-hepatocytes), an inhibitor of Kupffer cell activation. The decline of rOAT2 mRNA expression observed in the normal hepatocytes was enhanced by LPS treatment, but not in the Gd-hepatocytes. The LPS-dependent enhancement in the decline of rOAT2 mRNA expression did not occur when the normal hepatocytes were treated with AG or actinomycin D. When the Gd-hepatocytes were treated with SPER/NO, an NO donor, the rOAT2 mRNA expression declined markedly. Combined, our results suggest that rOAT2 mRNA expression in hepatocytes is down-regulated by NO at least at the transcriptional step.
Cha
Seok Ho
SH
Nitric Oxide Radical Toxicology Research Center, College of Medicine, Inha University, Incheon, Korea.
Kim
Hong Pyo
HP
Jung
Nam-Hee
NH
Lee
Woon Ki
WK
Kim
Ju Young
JY
Cha
Young-Nam
YN
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D015536:Down-Regulation / Q000502:physiology*; D022781:Hepatocytes / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D027361:Organic Anion Transporters / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D027361:Organic Anion Transporters; D012333:RNA, Messenger; D009569:Nitric Oxide