[Apoprotein B in high density lipoproteins: variations according to the type of hyperlipoproteinemia].

Two techniques for the separation of high density lipoproteins are compared: ultracentrifugation and concanavalin A precipitation. There is a significant correlation for the high density lipoproteins cholesterol levels found by the two techniques (r = 0.66, p less than 0.001). Nonetheless ultracentrifugation gives higher values than precipitation. When the ultracentrifuged high density lipoproteins fraction was precipitated with concanavalin A, a highly significant correlation was found between the amounts of apoprotein B and cholesterol present in the precipitate (r = 0.90, p less than 0.001). These results indicate the presence of a subfraction of the ultracentrifuged high density lipoproteins fraction which is precipitated by concanavalin A and which contains apoprotein B. This fraction is present in varying proportions according to the type of hyperlipoproteinemia, types iib and IV having the greatest amounts. In conclusion, only the concanavalin A precipitation technique results in a separation of apoprotein B-containing and non-apoprotein B-containing lipoproteins. This renders it preferable to ultracentrifugation for determining atherogenicity risks.