EFFECT OF OCTREOTIDE ON FASTING GALL-BLADDER EMPTYING, ANTRODUODENAL MOTILITY, AND MOTILIN RELEASE IN ACROMEGALY

Subcutaneous octreotide (Sandostatin) injections lead to gall stone fo rmation in 13-50% of acromegaly patients during one year of therapy. T his study explored the effects of octreotide on interdigestive gall bl adder emptying, antroduodenal motility, and motilin release. Ambulator y antroduodenal manometry was performed in six acromegaly patients bef ore and after two months of octreotide therapy (100 mu g thrice daily, subcutaneously). Ultrasonographic gall bladder volume measurements an d plasma motilin concentrations were obtained during two migrating mot or complex (MMC) cycles. Before octreotide treatment, nine of 26 phase III activities started in the antrum and 17 of 26 in the duodenum whe reas during treatment 47 of 48 of phase III activity started in the du odenum (p<0.05). Before treatment, interdigestive gall bladder emptyin g (mean (SEM) 39.9 (4.0)% of maximal fasting volume) and plasma motili n peaks preceded antral phase III but not duodenal phase III. During o ctreotide therapy no significant motilin fluctuation or gall bladder e mptying was seen. Fasting gall bladder volume increased from 40.9 (9.1 ) ml before to 68.0 (14.8) ml (p<0.05) during octreotide treatment. In conclusion, two months' treatment with octreotide increases the numbe r of duodenal phase III Like activity and virtually abolishes antral p hase III, plasma motilin peaks, and interdigestive gall bladder emptyi ng. These effects might contribute to the high risk of gall stone form ation during longterm octreotide treatment.