Submitted on August 27, 2008
Revised on November 19, 2008
Accepted on November 25, 2008
Lymphatic and Portal Vein Absorption of Organochlorine Compounds in Rats
Ronald J. Jandacek1*, Therese Rider2, Qing Yang2, Laura A. Woollett2, and Patrick Tso3
1 University of Cincinnati School of Medicine
2 University of Cincinnati
3 University of Cincinnati Medical Center
* To whom correspondence should be addressed. E-mail: ronald.jandacek{at}uc.edu.
The route of absorption of ingested compounds is a determinant of their distribution and metabolism. Portal vein absorption results in direct transport to the liver, where metabolism may take place before extra-hepatic delivery. Lymphatic absorption can result in delivery of parent compound to non-hepatic tissues. Understanding the fate of an ingested compound requires determination of the importance of each of these routes. Portal vein absorption can be estimated from the difference in concentrations of an ingested compound between the portal vein and peripheral vessel blood. To make these estimations, one must make assumptions based on estimates of flow rate and dilution. We report here methodology that allows a direct measurement of portal vein absorption that is independent of these assumptions. Mesenteric lymph was diverted from rats by cannulation. Portal blood was sampled after duodenal infusion of a bolus of compound of interest along with a portal absorption marker, 3-O-methylglucose. Since lymph was diverted, the appearance in portal blood was solely the result of portal absorption. Absorption was quantified by the areas under the curve for the compound and marker. Portal absorption was a function of the octanol/water partition coefficients for four organochlorine compounds: hexachlorobenzene; pentachlorophenol; DDT; and its metabolite, DDE.
