Octreotide increases the proportions of arachidonic acid-rich phospholipids in gall-bladder bile

Background and aims: Octreotide treatment of acromegalic patients induces c holesterol gallstone formation, in part by impairing cholecystokinin releas e and gallbladder contraction. However, there are few data on the effect of octreotide on biliary arachidonic acid-rich phospholipids or mucin glycopr otein, factors which also influence cholesterol gallstone formation. Methods: In acromegalic patients studied before and during 3 months of octr eotide treatment, we measured mucin glycoprotein concentrations and the mol ecular species of phosphatidylcholine, and related the results to the chole sterol saturation and percentage of deoxycholic acid in gall-bladder bile. Results: The relative proportions of the major arachidonic acid-rich phosph atidylcholine species, PC 16:0-20:4 and PC 18:0-20:4, increased significant ly during octreotide treatment. These changes were associated with a rise i n the cholesterol saturation index and a non-significant twofold increase i n mucin glycoprotein concentration. There were significant correlations bet ween PC 16:0-20:4 and the cholesterol saturation index, percentage of vesic ular cholesterol and percentage of deoxycholic acid in gall-bladder bile. Conclusions: In acromegalic patients, octreotide increases the proportions of arachidonic acid-rich phospholipids, with associated rises in: (a) the c holesterol saturation index and percentage of vesicular cholesterol, and (b ) the percentage of deoxycholic acid in gallbladder bile-changes similar to those found in patients with cholesterol-rich gall-bladder stones.