Nuclear topoisomerase I and DNase activities in rat diethylnitrosamine-induced hepatoma, in regenerating and fetal liver.
DNase activity in the presence of Ca2+ + Mg2+, Mg2+ alone, Mn2+ alone, or EDTA, and topoisomerase I activity were measured in nuclear extracts of diethylnitrosamine (DEN)-induced hepatomas, regenerating, fetal, and normal rat livers. In hepatoma tissue, the Ca/Mg-dependent DNase activity was lower than in normal tissue and nearly the same as in fetal liver. In the poorly differentiated hepatomas, Mn-dependent DNase activity was higher than in both moderately and well differentiated ones and than in normal liver tissue. The activity of topoisomerase I in hepatomas and in regenerating liver was lower than in normal liver tissue.
Basnakian
A G
AG
Institute of Biological and Medical Chemistry, USSR Academy of Medical Sciences, Moscow.
Boubnov
N V
NV
Kirsanova
I D
ID
Votrin
I I
II
D000818:Animals; D002413:Cations, Divalent; D002467:Cell Nucleus / Q000201:enzymology; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism*; D004052:Diethylnitrosamine / Q000494:pharmacology; D008113:Liver Neoplasms / Q000201:enzymology*; D008115:Liver Regeneration / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D002413:Cations, Divalent; D004052:Diethylnitrosamine; D003851:Deoxyribonucleases; D004264:DNA Topoisomerases, Type I