Evaluation of gel chromatography for plasma lipoprotein fractionation.

The fractionation of lipoproteins of normal and hyperlipidemic subjects on a column of 2% agarose was compared with ultracentrifugation and paper electrophoresis procedures. The following results were obtained. (a) Plasma lipoproteins were eluted successively from the column in the four overlapping peaks of chylomicrons, very low density lipoproteins, low density lipoproteins, and high density lipoproteins.

Determination of individual conjugated bile acids in human bile.

A method has been developed and validated for the determination of the six major conjugated bile acids, cholesterol, and total phospholipids in bile of human subjects previously injected with 4-(14)C-cholesterol. The procedure is designed for use with 5-10 ml of duodenal or T-tube bile and eliminates difficulties associated with existing methods for bile acid determination, in particular the requirement for preliminary saponification under pressure or the use of paper chromatography. Saponification under pressure is employed only in steps where partial destruction of the steroid moiety of conjugated bile acids is not a crucial matter.

1,2-3-H cholesterol as a tracer in studies of human cholesterol metabolism.

1,2-(3)H-Cholesterol was fed to a subject together with 4-(14)C-cholesterol at a known (3)H/(14)C ratio. The ratio was satisfactorily preserved in cholesterol recovered from plasma, red cells, and bile, and in bile acids of bile. Isotopic fractionation was seen during thin-layer chromatographic isolation of cholesterol.