Abstract
In vitro esterification of labeled cholestanol was demonstrated in normal plasma as well as in plasma from patients with cerebrotendinous xanthomatosis, the rate of esterification being about 70 per cent of that of cholesterol. In familial lecithin:cholesterol acyltransferase (LCAT) deficiency no esterification either of cholesterol or of cholestanol occurred, but the esterifying activity was restored by the addition of partially purified LCAT. Plasma LCAT therefore seems to be responsible also for the esterification of cholestanol.