Influence of aging on the carcinogen-induced protein kinase activity in rat liver cell nuclei.
A carcinogen-induced increase in a protein kinase activity was found in cell nuclei of rat liver. The enzyme was extracted from isolated nuclei with a hypotonic buffer, retained to an anion-exchange column, eluted with 0.15 M NaCl containing solution and to be measured for the activity with casein as the substrate, showing a nature of a casein kinase. The change in the activity during the course of aging was studied with 5-, 10-, and 50-week old Wistar male rats. The activity was highest in 5-week-old rat but decreased in 10- and 50-week-old animal. A hepatocarcinogen, thioacetamide, induced an increase in activity in 10-week old rats but rather decreased in 5- and 50-week-old rats. Aging suppresses the activity of this unique enzyme. Thioacetamide abolishes this suppression resulting in an increase in the activity of the enzyme at a certain stage of aging.
Sakai
Tetsuo
T
Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan.
Sato
Ritsuko
R
Mizuno
Hitoshi
H
Matsuo
Hideo
H
Nomura
Akira
A
Koh
Shunhan
S
Gondo
Hideki
H
Wakizaka
Akira
A
D000375:Aging / Q000502:physiology*; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D002364:Caseins / Q000378:metabolism; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013853:Thioacetamide / Q000494:pharmacology*
D002273:Carcinogens; D002364:Caseins; D013853:Thioacetamide; D011494:Protein Kinases