Summary: This study was carried out to compare the hepatoprotective
effect of methionine on paracetamol treated rats at both the peaks of
toxicity and absorption. Female Wistar rats were divided into 17 groups
consisting of eight rats per group and treated with different doses of
paracetamol/methionine (5:1). Each control rat received 5 ml of
physiologic saline. The study was terminated at two different end
points –the 4th & 16th hours. Results show that rats
administered with toxic doses (1000 mg/kg; 3000 mg/kg; 5000 mg/kg BW)
of paracetamol exhibited significant increases (p<0.05) in the
levels of ALT, AST, γ- GT compared with controls. These increases
were much higher at the 16th than 4th hour but serum total protein,
albumin and globulin were significantly decreased (p<0.05) by the
end of the 16th hour. Histology results of rats in the 3000 & 5000
mg/kg (by the end of the 16th hour) confirmed hepatic damage; light
microscopic evaluation of liver showed remarkable centrilobular
necrosis. Moreover, the presence of mononuclear cells in liver section
of rats intoxicated with APAP (5000 mg/kg) suggests a possible
involvement of inflammatory process which resulted in regurgitation of
bilirubin leading to its elevated level as well as increase activity of
ALP. The hepatoprotective effect of methionine, on the other hand, was
demonstrated in these rats at the 4th & 16th hours, and both
results were comparable and therefore not significantly different
(p>0.05) but elevation in GGT level still persisted. In conclusion,
data obtained from this study suggest that these agents may be capable
of inducing GGT, although further study is required to establish a
possible relationship between methionine and this enzyme in some other
animal species