[Pharmacological studies of N-(2-mercapto-2-methylpropionyl)-L-cysteine (SA 96). VI. Effects on vitamin B6, metals and skin collagen in rats].

N-(2-Mercapto-2-methylpropionyl)-L-cysteine (SA 96), an antirheumatic agent, and the main metabolite of SA 96, N-[2-methyl-2-(methylthio)propionyl]-L-cysteine (SA 679), were investigated for the effects on vitamin B6 (VB6), metals and skin collagen in rats in comparison with D-penicillamine (D-Pc). SA 96 had no effect on VB6 amount in serum and liver at doses of 30 mg/kg and 150 mg/kg, p.o., for 28 days, but SA 96 as well as SA 679 lowered the level in the liver slightly at a dose of 600 mg/kg. On the other hand, D-Pc lowered the VB6 level markedly both in serum and liver at doses of 150 mg/kg and 600 mg/kg, p.o., for 28 days. SA 96, SA 679 or D-Pc had no effect on urinary VB6 excretion. The degree of complexing of SA 96 as well as SA 679 with pyridoxal-5-phosphate in vitro was very slight as compared with D-Pc. SA 96 and D-Pc increased Cu and Zn excretion in urine, decreased Cu level both in serum and liver, and increased Zn level in serum. However, the degree of these effects of SA 96 on the metals was very slight as compared with D-Pc. SA 96 or SA 679 had no effect on skin collagen, neither soluble nor insoluble collagen, but D-Pc increased soluble collagen markedly. In addition, at a dose of 600 mg/kg, D-Pc decreased insoluble collagen.(ABSTRACT TRUNCATED AT 250 WORDS)