[Pharmacological studies on N-(2-mercapto-2-methylpropanoyl)-L-cysteine(SA96). IV. Effects of SA96 and its main metabolite, SA679, on denaturation of human gamma-globulin and adjuvant arthritis in rats].

SA96 and its main metabolite, SA679, were investigated for their effects on denaturation of human gamma-globulin and bovine serum albumin (BSA) and on adjuvant arthritis in Lewis rats. The heat denaturation of human gamma-globulin and BSA enhanced by Cu2+ was inhibited by SA96, SA679 and D-penicillamine, and the inhibitory effect of SA96 was the most potent. In adjuvant arthritis rats, SA96 given orally at a dose of 10 mg/kg from the same day as the adjuvant injection inhibited significantly the swelling of adjuvant treated foot and untreated foot, increase of the relative organ weights of the adrenals, liver and kidney, and increase of serum Cu concentration; but at a dose of 100 mg/kg, it did not show any effects on these parameters. On the other hand, SA96 given from three days before the adjuvant injection showed the inhibitory effects at a dose of 100 mg/kg as well as 10 mg/kg. These results suggest that the effect of SA96 on adjuvant arthritis in rats depends on its administration schedule. SA679 also inhibited the adjuvant arthritis at a dose of 100 mg/kg, but its effect was less potent than that of SA96.