RESUMO
Effect of dimethyl sulphoxide (DMSO) on mitochondrial biogenesis in regenerating rat liver and cells of Saccharomyces cerevisiae during aerobiosis has been studied by monitoring the cytochrome oxidase activity. A single dose of DMSO (275 mg/100-125 g body wt) to normal rats stimulated cytochrome oxidase activity in liver mitochondria while the same dose to partial hepatectomized rats inhibited the enzyme activity. Administration of low dose of DMSO (92 mg/100-125 g body wt) to partial hepatectomized rats did not alter the enzyme activity. Anaerobic cells of S. cerevisiae on aerobiosis for 2 hr attained cytochrome oxidase activity level on par with aerobic cells. Inclusion of DMSO (275 mg/100 ml) in the growth medium of S. cerevisiae during respiratory adaptation exerted partial inhibitory effect on the formation of cytochrome oxidase at 2 hr period, while the 10-fold concentration inhibited the enzyme formation completely. However, the inhibitory effect of DMSO on enzyme formation was abolished on prolonged growth (18 hr and above), while these doses had no influence on cytochrome oxidase in aerobic cells of S. cerevisiae. The results imply that DMSO may be exerting its effect on the assembly of subunits into active enzyme complex during mitochondrial biogenesis.