X-Message-Number: 12132
Date: Wed, 14 Jul 1999 21:21:42 -0700 (PDT)
From: Doug Skrecky <>
Subject: dmso and formaldehyde

  Govindwar SP.  Dalvi RR.
  Department of Physiology and Pharmacology, School of Veterinary Medicine,
  Tuskegee University, AL 36088.
  Stimulatory and inhibitory effects of dimethyl
  sulfoxide on microsomal aniline hydroxylase activity.
  Toxicology Letters.  55(3):317-23, 1991 Mar.
  Dimethyl sulfoxide (DMSO) at a single dose
  of 3 ml/kg body wt, administered i.p. to male rats, caused a significant
  increase in the hepatic microsomal aniline hydroxylase activity. However, the
  level of cytochrome P-450, the activities of NADPH-cytochrome c reductase,
  benzphetamine N-demethylase and aminopyrine N-demethylase were unchanged at
  24 h post-treatment. DMSO interacted with control rat liver microsomes in
  vitro and produced a type II spectral change (peak at 420 nm and trough at
  392 nm). On the other hand, liver microsomes from DMSO-treated rats gave
  qualitatively similar spectra, but with a higher magnitude of binding. Liver
  microsomes from DMSO-treated rats showed a 3.4-fold increase in Vmax for
  aniline hydroxylase, while Km was found to be the same when compared with
  control rat liver microsomes. In vitro addition of 6 mM DMSO to microsomal
  incubations from control and DMSO-treated rats caused a 9-fold and a 25-fold
  increase in Km, respectively, while Vmax values for aniline hydroxylase were
  unchanged. When DMSO (6 mM) was incubated with rat liver microsomes in the
  presence of NADPH, there was formation of formaldehyde. The results suggest
  an interaction of DMSO with microsomal cytochrome P-450.

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