Delayed plasma clearance and hepatic uptake of lymph chylomicron 14C-cholesterol in marginally zinc-deficient rats.
Previously, chylomicrons from marginally zinc-deficient rats were shown to be abnormally large, with markedly reduced levels of apoproteins C and E. In the present study, effects of such changes on the plasma clearance and hepatic uptake of chylomicron cholesterol were investigated in rats fed 3 ppm of zinc (ZD), as compared with those fed 30 ppm of zinc (CT). The rate of plasma clearance was determined by plasma 14C-radioactivity at different intervals after intravenous injection of lymph chylomicrons labeled in vivo with 14C-cholesterol. The 14C-clearance curves were nonlinear, consisting of an initial rapid phase followed by a slow phase of clearance. The initial 14C-clearance was significantly (p less than 0.05) delayed whether the labeled chylomicrons from ZD donors were injected into ZD or CT recipients. The hepatic 14C-recovery in extracted lipids was also significantly lower in ZD rats. The present data provide first evidence that a marginal level of zinc deficiency produces a significant delay in the plasma clearance and hepatic uptake of chylomicron cholesterol. This may be attributable in part to the molecular alterations of chylomicrons induced by zinc deficiency.
D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002250:Carbon Radioisotopes; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002914:Chylomicrons / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D015032:Zinc / Q000172:deficiency* / Q000494:pharmacology
D002250:Carbon Radioisotopes; D002914:Chylomicrons; D002784:Cholesterol; D015032:Zinc