Absorption and distribution of [l-14C]dolichol intubated into rats

[1-l4C]Dolichol was mixed in vitro with sunflower seed oil and intubated into rats. Radioactivity began to appear in the blood at 3 h and peaked after about 6 h. The absorbed radioactivity was rapidly cleared from the blood. At 7.5 h postintubation two thirds of the radioactivity in the serum was associated with chylomicrons and about one quarter with the high density lipoproteins. At 12 h the proportion of the radioactivity in the chylomicrons had fallen to one third and that in the high density lipoproteins had increased to one half of the total. Less than 0.02% of the dose was found in the tissues after 12 h. Liver and blood each contained about one third of the total, with smaller amounts in the lungs and spleen. The heart, testes, brain, and kidneys contained only traces of radioactivity. After 12 h most of the radioactivity in the tissues and feces was present as [1-l4C]dolichol. The radioactive compounds in the urine (about 0.05% of the dose) were more polar than [1-l4C]dolichol as determined by thin-layer chromatography.