Protective effect of methionine against vinyl chloride-mediated depression of non-protein sulphydryls and cytochrome p-450.

Potentiality of a protective effect of methionine against hepatotoxic action of vinyl chloride (VC) was assessed on rats, induced with phenobarbital and thereafter exposed to 50 000 ppm VC for 5 h. This extremely high dosage of VC warranted the appearance of drastic symptoms of liver injury in the course of 20 h postexposure. DL-Methionine in a dose of 1 g/kg given by gavage prior to the VC-exposure counteracted both the BC-provoked depletion of non-protein sulphydryls and destruction of cytochrome P-450 in the liver. In the methionine-pretreated rats the phenobarbital-induced synthesis of microsomal proteins in the livers was maintained during the post-exposure period, contrary to the non-pretreated animals. It may be justified to apply methionine as a prophylactic agent in cases of occupational exposure to VC.