The Influence of Sodium Glycocholate on the Enzymatic Synthesis and Hydrol- Ysis of Cholesterol Esters in Blood Serum*

The presence of a cholesterol esterase in blood serum was demonstrated by the finding (1) that a marked esterification of free cholesterol occurs on incubation of untreated serum, but does not occur on incubation of serum which has previously been heated for 1 hour at 55-60’.1’ In studying this reaction further it was of interest to ascertain the effect of bile salts, first, because it is known from many investigations that they influence the enzymatic hydrolysis and synthesis of esters (3, 4) and, second, because it seemed possible that the increased proportion of free cholesterol, usually found in the serum of persons with diseases of the liver, might be associated with the accumulation of bile salts which presumably occurs in such conditions. In the present investigation the concentration of total and free cholesterol was determined before and after incubation of human and dog serum to which varying amounts of sodium glycocholate had been added. The bile salt exerted a marked effect which was