Changes in the expression of lipid-mediated signal-transducing enzymes in the rat liver after partial hepatectomy.
Prostaglandins (PGs), metabolites of arachidonic acid, and other lipid mediators produced by phospholipases C (PLC) and D (PLD) are thought to play important roles in hepatocyte proliferation. The present study examined lipid-mediated signaling in the rat liver after partial hepatectomy (PH). Rats were killed 1-48 h after 70% PH and the remaining liver tissue was removed. The mRNA and protein levels of some signaling molecules were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, respectively. The levels of hepatocyte growth factor (HGF) mRNA showed a biphasic change, peaking 3 h and 9 h after PH. The expression of PLCdelta4 peaked at 12 h, but no significant changes in the expression of PLCbeta1 and PLCgamma1 were seen after PH. T he enzymes involved in PG production, namely, the expression of cytosolic PLA2 and cyclooxygenase 1 (COX1), remained constant after PH. However, the mRNA of COX2 increased transiently at 3 h, and Western blot analysis showed an increase in COX2 protein at 12 h. The expression of PLD1b peaked at 9 h and PLD1a at 12 h, whereas the expression of PLD2 remained consistent for 24 h. These results suggest that transcriptional controls may act for PLCdelta4, PLD1a/b, and COX2 during hepatocyte regeneration after PH.
Watanabe
A
A
Second Department of Surgery, Gifu University School of Medicine, Japan.
Nakashima
S
S
Adachi
T
T
Saji
S
S
Nozawa
Y
Y
D000818:Animals; D015153:Blotting, Western; D051546:Cyclooxygenase 2; D005786:Gene Expression Regulation; D006498:Hepatectomy; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D022781:Hepatocytes / Q000201:enzymology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000601:surgery*; D008297:Male; D010739:Phospholipase D / Q000096:biosynthesis* / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000096:biosynthesis* / Q000378:metabolism
D007527:Isoenzymes; D012333:RNA, Messenger; D017228:Hepatocyte Growth Factor; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D010738:Type C Phospholipases; D010739:Phospholipase D