In vitro Metabolism of p,p′DDT in Pigeon Liver

Abstract

DESPITE the widespread use of DDT^*, knowledge of its metabolism in vertebrates is incomplete, and is based almost entirely on experiments carried out on mammals in vivo. There have been no unequivocal reports of in vitro conversions to support these findings. Woodward, Davidow and Lehman¹ have reported the disappearance of DDT from homogenized liver of rabbits injected intravenously with emulsions of DDT prior to death, but no metabolites were isolated. Judah² incubated rat liver, kidney and diaphragm with DDT, but found no DDD or DDE and obtained only a very small conversion to DDA. Peterson and Robison³ have recently put forward a metabolic pathway for DDT in rats which was based on feeding the pesticide and its postulated metabolites, and analysing residues in the liver and kidney. In the course of these experiments, liver homogenate was incubated for 6 days with DDT, and DDD was isolated with a final ratio of DDT : DDD of 1 : 3, although, as the authors point out, this may have been due to bacterial action. No in vitro work has been reported with birds, which are probably the vertebrates most at risk from the agricultural use of DDT. We now wish to report the in vitro conversion of DDT to DDD and DDE by incubation of both homogenate and slices of pigeon liver.