EFFECT OF ALCOHOLS AND TOLUENE UPON METHYLENE CHLORIDE-INDUCED CARBOXYHEMOGLOBIN IN THE RAT AND MONKEY

The effects of ethanol (EtOH), methanol (MeOH), isopropanol (IpOH), and toluene upon methylene chloride (MeCl)-induced carboxyhemoglobin (COHgb) levels were investigated in rats and monkeys. Inhalation studies in rats exposed to 50-5000 ppm MeCl produced a linear dose-response relationship and demonstrated that COHgb formation was weight (age) dependent. Rats exposed for 1 hr to 5000 ppm MeCl and 8000 ppm EtOH or 5000 ppm MeCl and 1350 ppm IpOH showed a significant inhibition of COHgb production while similar exposure to MeCl and 11,000 ppm MeOH did not alter the levels. The ip administration of MeOH to rats 30 min prior to a MeCl inhalation challenge caused a significant inhibition of COHgb formation. Monkeys exposed for 3 hr to 1000 ppm MeCl and 330 ppm MeOH had peak COHgb levels similar to those of MeCl controls. Monkeys exposed for 1 hr to 1800 ppm toluene, 4300 ppm MeOH, and 4650 ppm MeCl showed COHgb inhibition as did rats when pretreated ip with toluene and challenged by inhalation with MeCl. All solvents tested produced inhibition of MeCl-induced COHgb, and neither the rat nor the monkey demonstrated the MeOH potentiation of COHgb that has been reported to occur in man. © 1979.