A 90-Day Vapor Inhalation Toxicity Study of Methyl Ethyl Ketone

A 90-Day Vapor Inhalation Toxicity Study of Methyl Ethyl Ketone.Cavender, F.L., Casey, H.W., Salem, H., Swenberg, J.A. and Gralla,E.J. (1983). Fundam. Appl. Toxicol. 3: 264–270. Male andfemale Fischer 344 rats were exposed to 0, 1250, 2500, or 5000ppm methyl ethyl ketone (MEK) vapors 6 hours per day, 5 daysper week for 90 days. The 90-day exposures had no adverse effecton the clinical health or growth of male or female rats exceptfor a depression of mean body weight in the 5000 ppm exposuregroup. The 5000 ppm animals had a slight but significant increasein liver weight, liver weight/body weight ratio, and liver weight/brainweight ratio at necropsy. Serum glutamic-pyruvic transaminase(SGPT) activity in the 2500 ppm female rats was elevated whilethe 5000 ppm female rats exhibited significantly decreased SGPTactivity. In addition, alkaline phosphatase, potassium and glucosevalues for the 5000 ppm female rats were increased. Specialneuro-pathological and routine pathological studies did notreveal any lesions that could be attributed to MEK exposure.