ISOLATION AND QUANTITATION OF RAT HEPATIC METALLOTHIONEIN AFTER METHOTREXATE ADMINISTRATION

Metallothionein (MT) function has usually been related to metal metabo lism. However, it recently seems that this protein has a role in the t oxicity prevention of anticancer drugs to non-malignant cells. In this sense, we have studied the effect of Methotrexate (MTX) administratio n, 9 mg/kg body weight/day, for six days in rats. So, a body weight de crease takes place on the sixth day of treatment, that was correlated with the liver weight/body weight ratio. A liver protein concentration increase is observed on the fourth day of MTX treatment, that bears a nd increase in MT concentration determined by Cd-hemoglobin radioassay . MT isolation was carried out by gel filtration chromatography. The h igher MT induction was observed at fourth MTX doses. Reverse-phase hig h-presure liquid chromatograpy (RP-HPLC) was used to characterize the liver isometal- lothioneins. Rat liver MT induced by cadmium was used as standard to determine the MT concentration of our samples. The MT l evels determined by RP-HPLC were higher than the ones determined by On osaka methods.