[The activity of nuclear endonucleases and topoisomerases in the liver of rats and in diethylnitrosamine-induced tumors].
The DNA endonuclease (Aendo) and DNA topoisomerase (Atopo) activities in liver nucleus extracts of normal rats, in DENA-induced hepatomas and in liver tissues around tumours were investigated. The profile of nuclear endonucleases measured in the presence of 2 mM CaCl2 + 5 mM MgCl2, or 5 mM MnCl2, or 5 mM MgCl2, or 2 mM CaCl2 (pH 7.4), or I mM EDTA (pH 5.0) was different in normal and tumour tissues. Mn2+-dependent endonuclease was the main endonuclease in the tumour tissue, whereas Ca2+, Mg2+-dependent endonuclease was the main one in the normal liver and in the tissue around the tumour. An increase in the Mn2+-dependent endonuclease activity correlated with a decrease in the hepatoma differentiation level. Atopo of types I and II increased in the tissue around the tumour. Aendo and Atopo of cellular nuclei decreased in animals given DENA without the liver tumour.
Basnak'ian
A G
AG
Bubnov
N V
NV
Kirsanova
I D
ID
Votrin
I I
II
D000818:Animals; D002021:Buffers; D002467:Cell Nucleus / Q000032:analysis / Q000201:enzymology*; D004264:DNA Topoisomerases, Type I / Q000032:analysis / Q000378:metabolism*; D004052:Diethylnitrosamine / Q000633:toxicity*; D004720:Endonucleases / Q000032:analysis / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000032:analysis / Q000139:chemically induced / Q000201:enzymology*; D008297:Male; D008722:Methods; D051381:Rats; D011919:Rats, Inbred Strains
D002021:Buffers; D004052:Diethylnitrosamine; D004720:Endonucleases; D004264:DNA Topoisomerases, Type I
Aktivnost' iadernykh éndonukleaz i topoizomeraz v pecheni krys i opukholiakh, indutsirovannykh diétilnitrozaminom.