Tissue uptake of DDT is independent of chylomicron metabolism

To determine whether DDT uptake from chylomicrons (CM) into tissues is coincident with CM core lipid uptake.

CM were collected from mesenteric lymph duct cannulated, male Sprague-Dawley rats administered olive oil containing 3H-Cholesterol (converted to cholesterol ester (CE) during absorption through the intestine) and 14C-DDT by oral gavage. The CM were suspended in normal saline and 400 microL (containing 0.11 microCi/mL 14C-DDT and 0.15 microCi/mL 3H-CE) was administered via the jugular vein to the recipient rats. The blood was sampled periodically over 30 min from the carotid artery and at the end of the experiment the adrenal glands, brain, fat, heart, liver and spleen were collected. The concentration of 14C-DDT and 3H-CE in whole blood samples and tissue samples was then determined.

DDT was removed from the whole blood and, therefore, CM at a significantly faster rate than CE (alpha = 0.05). The tissue distribution of DDT was also different from that of CE, and DDT was particularly concentrated in the retriperitoneal fat and brain. For DDT, the values for VBdB and Cl were significantly higher compared with those determined for CE.

DDT is absorbed predominantly via the intestinal lymphatic system in association with CM and accumulates in fatty tissues. This study furthers the understanding of the process of DDT uptake from CM into tissues and demonstrates that the uptake of DDT into tissues is faster than and independent of the uptake of CM core lipid (using CE as a marker). DDT was particularly concentrated in fatty tissues, accounting for its relatively high VBDB.