Aspirin induces short-chain free fatty acid accumulation in rats.

Aspirin is used for the prophylaxis of infarction. A low dose of aspirin is effective for the prophylaxis of myocardial infarction, whereas a higher dose is necessary for that of stroke. Salicylic acid, the in vivo metabolite of aspirin, inhibits the beta-oxidation of short-chain fatty acids. Accordingly, drinking water containing 400, 800, or 1200 mg/l aspirin was given to each of eight rats for 30 days to determine the serum short-chain fatty acid levels. Analysis of variance and a post-hoc Fisher's protected least significant differences test revealed significantly increased levels (P < 0.05) of monocarboxylic acids, n-hexanoate, n-octanoate, n-decanoate, n-dodecanoate, and dicarboxylic acids, adipate (C6,) and suberate (C8): 78.7 +/- 36.2, 61.1 +/- 30.6, 215 +/- 151, 47.5 +/- 24.0, 3.64 +/- 2.09 and 1.71 +/- 1.45 micromol/l in the 800 mg/l aspirin group compared to 23.8 +/- 12.3, 20.1 +/- 9.0, 24.3 +/- 12.1, 6.3 +/- 5.6, 0.56 +/- 0.50 and 0.44 +/- 0.25 micromol/l in the control group, respectively. These levels were also increased in the 400 or 1200 mg/l aspirin groups but less so. These findings may help us to understand the aspirin toxicity in Reye's syndrome.