The half-lives of dolichol and dolichyl phosphate in rat liver.

Rat liver dolichol and dolichyl-P were labeled by injection of [3H]mevalonate into the portal vein and their rates of synthesis and breakdown determined. In the initial phase the radioactivity appeared in alpha-unsaturated polyprenols. Subsequent saturation required 90 min. The half-lives of dolichols in microsomes were between 80 and 118 h, and shorter dolichols had shorter values of T1/2. The half-lives of dolichols in lysosomes were between 115 and 137 h, while microsomal dolichyl-P exhibited a T1/2 of 32 h. Injected dolichol was recovered in the lysosomes of hepatocytes and exhibited a rate of breakdown which was slower than that of the endogenous compound. These results indicate differences in the catabolism of dolichol at different subcellular locations, as well as differences between the catabolism of dolichol and dolichyl-P.