Metabolism by rats of 2-dodecylcyclobutanone, a radiolytic compound present in irradiated beef.

Alkylcyclobutanones (2-ACBs) are suspected cancer promoters and clastogens, which have raised concerns about the safety of irradiated foods. Currently there are few data on the metabolism of 2-ACBs, which makes it very important to study this aspect of 2-ACBs to evaluate their safety. The objectives of this experiment were to quantify 2-dodecylcyclobutanone (2-DCB; formed from palmitic acid) in the feces and adipose tissue of rats and to check for metabolites of 2-DCB in the urine. Six female Sprague-Dawley rats were administered 2-DCB (5 mg/day) in corn oil for 5 days via gavage. Six control rats did not receive 2-DCB. Feces and urine were collected daily, whereas adipose tissue was collected upon euthanasia. Hexane extracts of feces and adipose tissue were analyzed by gas chromatography-mass spectroscopy (GC-MS). Urine with and without added beta-glucuronidase was monitored for glucuronide complexes by hexane extraction and GC-MS. The total amount of 2-DCB recovered in feces was 1.78 +/- 0.63 mg at the end of 5 days, which represents between 3 and 11% of the total 2-DCB administered. The total amount recovered in the adipose tissue was 0.08 +/- 0.01 mg, which was approximately 0.33% of the total 2-DCB administered. No metabolites were recovered in any of the urine extracts. The results show that at most 11% of the 2-DCB was recovered unchanged in the feces and adipose tissue. This indicates that either most of 2-DCB is metabolized and rapidly eliminated from the body or stored at sites other than adipose tissue.