The aim of the study was to investigate the effect of the
dietary fat on selected parameters of
toluidines toxicity in rats during subchronic exposure. Three isomers of toluidine (ortho, meta, and para) were administered to rats in the diet for 1 and 3 months at levels 40, 80, 160 mg/kg/day in two kinds of diet containing either 4% or 14% fat. All doses of toluidine isomers produced a 1.5- to 9.8-fold increase in
methemoglobin (MetHb) level during both treatment periods. A distinct dose-response relationship was observed, especially for o- and
m-toluidine; the effect was generally greater in rats fed high-fat diet.
Reduced glutathione level in liver was increased in all treated groups, 1.5- to 5.1-fold, irrespective of the kind of diet. An increase in hepatic lipid peroxidation (
thiobarbituric acid reactive substances;
TBARS), 1.5- to 4.5-fold, was noticed in the majority of the treated groups. Generally, there was no consistent effect of diet except for
p-toluidine where the level of hepatic
TBARS was lower in rats fed high-fat diet. Blood
urea nitrogen (BUN) level in animals treated with all doses of o- and
m-toluidine was 1.3- to 5.0-fold higher in comparison with respective controls. No clear relationship between BUN level and the kind of diet was found. No effect of
toluidines on the activity of serum
aspartate aminotransferase (AST) and
sorbitol dehydrogenase (SDH) were observed. In the majority of groups treated for 30 and 90 days the amount of
toluidines in 24-h urine was lower in rats fed high-fat diet. Final
body weight gain in rats treated with o- and
p-toluidine (80 and 160 mg/kg
body weight [b.w.]) was lower as compared to controls. In summary the high-fat diet stimulated
methemoglobin formation in rats treated with o- and
m-toluidine and cause the decrease in the amount of
toluidines in 24-h urine. The high content of fat did not affect consistently the other parameters tested.