Uncoupling of oxidative phosphorylation in rat liver mitochondria following the administration of dimethyl sulphoxide.

A single intraperitoneal injection of 275 mg of dimethyl sulphoxide (DMSO) to rats (100-125 g body weight) effectively uncouples oxidative phosphorylation in liver mitochondria during the period from 2 hr to 5 day post-injection. Higher doses of DMSO are inhibitory to mitochondrial respiration. DMSO has however no uncoupling action on oxidative phosphorylation in vitro. On the other hand, dimethyl sulphide (DMS), a known metabolite of DMSO, brings about the uncoupling effect in vitro. The uncoupling of oxidative phosphorylation by normal mitochondria could also be achieved if these are pre-incubated (30 min at 0 degrees C) with the post-mitochondrial liver supernatant derived from rat injected with DMSO, 2-24 hr prior to sacrifice. These results provide explanation for the observed uncoupling effect exerted by DMSO in vivo.