KINETICS AND UPTAKE IN-VIVO OF OXIDATIVELY MODIFIED LYMPH CHYLOMICRONS

The metabolism of oxidized chylomicrons (ox-CMs) was investigated in v ivo. CMs from rats fed corn, linseed, or fish oil were oxidized by inc ubation with 2,2'-azobis(2-amidinopropane)hydrochloride (AAPH) or sodi um hypochlorite (NaOCl). Oxidized CMs had a rapid phase of clearance, followed by a slow phase. Clearance of ox-CMs was decreased for corn o il but increased for linseed and fish oil particles. Differences in ra tes of uptake between CM types or treatment were independent of the ra te of remnant formation, but were instead a consequence of decreased c learance. A greater triglyceride-to-cholesteryl ester ratio in liver s uggested that there was less lipolysis of ox-CM triglyceride prior to uptake. Hepatic uptake of ox-CMs was decreased, whereas there was incr eased uptake in spleen. However, the uptake by Kupffer cells of ox-CMs was 43% of total liver uptake after AAPH treatment and 59% after NaOC l treatment, compared with 21% for control CMs. Collectively, our data show that oxidation can have differential effects on the rate of clea rance of CMs and that ox-CMs are preferentially cleared by the reticul oendothelial system.