Expression of pyruvate kinase M2 in preneoplastic hepatic foci of N-nitrosomorpholine-treated rats.
The expression of the pyruvate kinase (PK) isoenzymes L and M2 was analysed in the livers of rats treated with the hepatocarcinogenic agent N-nitrosomorpholine (NNM) in the drinking water. In control animals L-PK expression was restricted to liver parenchymal cells, whereas M2-PK was detected in bile duct epithelial, blood vessel wall, endothelial and Kupffer cells. In rats treated with NNM proliferating oval cells were consistently L-PK negative and M2-PK positive, while the ductal cells of cholangiofibroses were clearly L-PK positive and coexpressed M2-PK. However, no morphological differentiation of ductal cells into hepatocyte-like cells was observed. In the clear and acidophilic cell foci storing glycogen in excess strong staining for L-PK was observed. In glycogen-poor foci induced by NNM a shift from L-PK to M2-PK expression takes place.
Steinberg
P
P
Institute of Toxicology, University of Mainz, Germany.
Klingelhöffer
A
A
Schäfer
A
A
Wüst
G
G
Weisse
G
G
Oesch
F
F
Eigenbrodt
E
E
D000818:Animals; D002273:Carcinogens; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology* / Q000473:pathology; D008297:Male; D009602:Nitrosamines; D011230:Precancerous Conditions / Q000139:chemically induced* / Q000201:enzymology* / Q000473:pathology; D011770:Pyruvate Kinase / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D002273:Carcinogens; D007527:Isoenzymes; D009602:Nitrosamines; C002741:N-nitrosomorpholine; D011770:Pyruvate Kinase