Male rats were fed 100 nM dichlorodiphenyltrichloroethane-14C in oil by gastric tube. Recovery of dichlorodiphenyltrichloroethane-14C in thoracic duct lymph was 60% in 12 hr. Lymph dichlorodiphenyltrichloroethane-14C (97%) occurred in lipoproteins of d<1.006, designated chylomicrons. Mechanical separation of chylomicron triglyceride core (labeled with triglyceride-3H) from chylomicron membrane (labeled with phospholipid-32P) showed that 97% dichlorodiphenyltrichloroethane-14C was present in triglyceride core. To investigate possible association of plasma clearance of the two core lipids, rats were pulse injected with chylomicrons, doubly labeled with triglyceride-3H and dichlorodiphenyltrichloroethane-14C. The decay of dichlorodiphenyltrichloroethane-14C in sequential serum samples was rapid (T1/2=2 min) and was independent of triglyceride-3H decay. In tissues removed 14 min after injection of chylomicrons, 30% administered dichlorodiphenyltrichloroethane-14C was found in liver but only 1% in adipose tissue. In hepatectomized (eviscerated) rats, the decay of serum dichlorodiphenyltrichloroethane-14C (T1/2=10 min) was also independent of and more rapid than triglyceride-3H decay. With sucrose density gradients, it was shown that chylomicron dichlorodiphenyltrichloroethane-14C transferred to higher density serum proteins in vitro and in vivo and to bovine albumin in vitro. Thus, dichlorodiphenyltrichloroethane was transported from intestine largely in the triglyderide phase of chylomicrons; disappearance of chylomicron-dichlorodiphenyltrichloroethane from the systemic circulation was rapid and partly independent of the presence of the liver and of triglyceride hydrolysis; some dichlorodiphenyltrichloroethane was transported from serum chylomicrons to albumin or other plasma proteins before tissue uptake.
KeywordsSucrose Density Gradient Intestinal Lymph Hydrophobic Lipid Chylomicron Triglyceride Lymph Chylomicron
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