Cholesterol Metabolism in Asterias Rubens

Abstract

[41-14C] choleslerol, (26J4C) cholesterol and (2-J4C) acetic acid were employed to study cholesterol metabolism in A. rubens,. With (4J4C) cholesterol highest radioactivity was found in free sterols (71 %) and steryl esters (24%) and smallest in glycendes and free fatty acids. Sterol sulphate were also heavily labelled. Fatty acid methyl esters prepared from glycerides and free fatty acids contained negligible radioactivity. Incorporation of (26J4C) cholesterol also resulted highest label in free sterols (7.5%) and steryl esters (19%). Saponification of steryl esters did not yield activity into fatty acid while sterols were labelled. Again sterol sulphales were labelled heavily. Incubation with (2J4C) acetic acid recorded highest activity in triglycerides (72%) and steryl esters (16%) while free sterol were significantly labelled (.5%). Moreover, situation of label in steryl esters and free sterols was opposite to that of (4J4C) cholesterol. Cholesterol catabolism did not produce labelled precursors or support re-utilization of carbon for lipid/cholesterol synthesis