Effect of methylene chloride on the oxyhemoglobin dissociation curve of rat and human blood
Dill, D.C.; Watanabe, P.G.; Norris, J.M.
Toxicology and Applied Pharmacology 46(1): 125-129
1978
ISSN/ISBN: 0041-008X PMID: 725938 Document Number: 138172
Methylene chloride is biotransformed in vivo to CO, and increased COHb concentrations occur in animals and man following exposure. Binding of CO to Hb causes a shift to the left in the position of the HbO2 dissociation curve (ODC), theoretically resulting in a diminished ability to release O2 in tissue. The effect of methylene chloride alone and in combination with CO on altering the ODC was studied. Methylene chloride and CO, alone and in combination, were incubated with rat and human blood in vitro and the position of the ODC was measured by the P50 [partial pressure of O2 at half-saturation of Hb at pH 7.4, 37.degree. C] value. Methylene chloride alone apparently had no effect on changing the P50 value of the ODC. Any shift to the left of the ODC following exposure to methylene chloride is due solely to CO formed from the biotransformation of methylene chloride. Speculation that methylene chloride increases the affinity of Hb for CO is not supported.