Early alteration in liver of rats fed 2-fluorenylacetamide investigated by L-ethionine probe.
The metabolic activity of liver of rats fed a diet containing 0.03% 2-N-fluorenylacetamide (FAA) was investigated using the probe of L-[ethyl-14C]ethionine (613 mumol L-E/100 g body wt.). Shortly after the onset of the carcinogenic regimen, the capacity of liver to accumulate S-adenosylethionine (SAE) began to decline, reaching its minimum (30% of the concentration in control rats) within 3 weeks. This decreased capacity to accumulate SAE results from the FAA-induced decrease in activity of ATP-L-methionine adenosyltransferase. The concentration of hepatic ATP assayed without L-ethionine (L-E) probe also declined during the first 2 weeks of the carcinogenic regimen, but then increased, attaining the normal values within 2 more weeks. Administering the L-E probe to the FAA-fed rats produced an even greater drop in hepatic ATP concentration during the first 2 weeks; however from the third week on, the L-E dose produced no depressing effect, despite the SAE accumulation remaining at its same depressed levels and, therefore, trapping the same amount of ATP as in the previous weeks. The results show that the modification of L-E metabolism and of ATP turnover, observed previously in DL-E fed rats, need not be specific for the carcinogen fed and can occur even when the carcinogens are metabolized by different enzymatic systems.
Brada
Z
Z
Papanicolaou Comprehensive Cancer Center, University of Miami School of Medicine, FL 33101.
Bulba
S
S
Hrstka
I
I
Pappatheodorou
S
S
D015073:2-Acetylaminofluorene / Q000008:administration & dosage / Q000494:pharmacology*; D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004032:Diet; D005001:Ethionine / Q000031:analogs & derivatives / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008716:Methionine Adenosyltransferase / Q000378:metabolism; D051381:Rats
C012167:S-adenosylethionine; D000255:Adenosine Triphosphate; D015073:2-Acetylaminofluorene; D008716:Methionine Adenosyltransferase; D000241:Adenosine; D005001:Ethionine