Two procedures for quantitative determination of
dolichol were studied and these were applied to analyze tissue and subcellular distribution. In the first procedure the
dolichols were oxidized with Cr2O3 and reduced with NaB3H4. The radioactivity in the individual
dolichols was measured using reversed-phase thin-layer chromatography. In the second procedure,
dolichols were analyzed by high-pressure liquid chromatography. For determination of dolichyl
phosphates the
lipid extract was subjected to
acid and alkaline hydrolysis, and after hydrolysis with
acid phosphatase the distribution was determined by high-pressure liquid chromatography. Recovery was monitored by the addition of
dolichol D15 and D23
phosphate to the homogenate. Rat spleen had the highest
dolichol content (114 micrograms/g) followed by lower content in rat liver and brain. The distribution pattern was similar in all organs, with 18 and 19
isoprene residues as dominating components. Human organs contain considerably higher concentrations of
dolichol, with the 19 and 20
isoprene residues as the main components. In rat liver, outer mitochondrial and Golgi membranes, lysosomes and plasma membranes contain considerable amounts of
dolichol. A drastic increase in
dolichol content was observed in rat liver hyperplastic nodules while human
liver cirrhosis and hepatocarcinoma showed a marked decrease in
dolichol. In the latter case, the distribution pattern was also changed. Of the total amount of
dolichol present in the tissues, 2% was phosphorylated in human liver, 10% in human testis and 18% in rat liver. In rat liver mitochondria and in microsomes 4 and 31%, respectively, of the
polyprenols were in activated form. The results demonstrated that
dolichyl phosphate and
dolichol concentrations were regulated by different mechanisms and that the two forms possessed an independent distribution.