A protein free diet uncovers the potential age-difference in the hepatic detoxifying system, glutathione S-transferase, in female mice.
Female C57BL mice of six different ages (from 6 to 26 months) were given a protein free-diet (PFD) for 1 week and then given a normal diet (ND). Mice were examined for enzyme activities of glutathione S-transferase (GST) in the hepatic cytosol fraction using l-chloro-2, 4-dinitrobenzene (CDNB) as substrate. Enzyme activities were very close among the six different age groups when examined for basal levels as well as after 1 week of PFD. However, a remarkable age difference became manifest when animals were examined 2 days after the start of ND refeeding following 1 week of PFD. In young animals (6, 8 months), activities became much higher than their respective basal levels while in old animals (24, 26 months) enzyme levels remained significantly lower than their basal levels on day 2 of ND refeeding. A significant negative linear correlation between enzyme activities (Y axis) and animal age (X axis) was demonstrated only on day 2 or 3 of ND refeeding, while in control animals or animals given 1 week of PFD diet, no significant correlation could be found between enzyme activities and animal age. We conclude that liver cytosolic GST activity is a function of animal age only after a dietary manipulation such as a PFD and ND refeeding, while basal GST activities remain stable throughout the observation period of animal age.
Carrillo
Maria-Cristina
MC
Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, 35-2, Sakaecho, Itabashi-ku, Tokyo, Japan.
Kanai
Setsuko
S
Miyasaka
Kyoko
K
Kitani
Kenichi
K
D000375:Aging / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D004044:Dietary Proteins / Q000494:pharmacology*; D004137:Dinitrochlorobenzene; D005260:Female; D005982:Glutathione Transferase / Q000378:metabolism*; D007202:Indicators and Reagents; D016014:Linear Models; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013047:Specific Pathogen-Free Organisms; D014118:Toxins, Biological / Q000378:metabolism
D004044:Dietary Proteins; D004137:Dinitrochlorobenzene; D007202:Indicators and Reagents; D014118:Toxins, Biological; D005982:Glutathione Transferase