title: The effects of vapreotide, a somatostatin analogue, on gastric acidity, gallbladder emptying and hormone release after 1 week of continuous subcutaneous infusion in normal subjects.
abstract: OBJECTIVE
  Somatostatin analogues (e.g. vapreotide) are used for treatment of acromegaly, endocrine tumours and variceal bleeding. The pharmacodynamic effects of vapreotide have, however, not been documented in the gastrointestinal tract. The aim of this study was to investigate the effects of continuous vapreotide administration on gastric acidity, gallbladder contraction and hormone release.
  
  
  METHODS
  Ten healthy males participated in this randomised, placebo-controlled, double-blind, crossover trial. A constant vapreotide (or placebo) infusion (1.5 mg day(-1) s.c.) was given for 7 days with a portable pump. Intragastric pH was monitored on days 2 and 7. Gallbladder volume was sonographically assessed and the maximal ejection fraction was calculated. In addition basal and postprandial plasma levels of gastrin and cholecystokinin (CCK) were measured.
  
  
  RESULTS
  After an initial increase in the median 24 h intragastric pH to a value of 2.6 on day 2, vapreotide's effect on pH decreased: (day 7: median pH=1.9; respective placebo values were 1.7 and 1.5). On the same days with vapreotide treatment, gallbladder contraction and plasma levels of CCK were reduced; maximal ejection fractions after meal stimulation were 18% and 20% (respective placebo values were 57% and 62%). Plasma gastrin levels were not changed with vapreotide treatment.
  
  
  CONCLUSIONS
  The short lasting effect of vapreotide on intragastric acidity suggests a down-regulation of somatostatin receptors during treatment. The lack of effect on gastrin indicates that the effects on gastric pH are not mediated by gastrin. Constant vapreotide infusion (but not placebo) reduced gallbladder contraction suggesting a long-lasting effect on biliary function.
authors: Division of Gastroenterology, University Hospital, Basel, Switzerland.
authors: M A
authors: MA
authors: Ritz
authors: J
authors: J
authors: Drewe
authors: A
authors: A
authors: Ziel
authors: P
authors: P
authors: Hildebrand
authors: P
authors: P
authors: Schneider
authors: N
authors: N
authors: Lahlou
authors: C
authors: C
authors: Beglinger
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000970:Antineoplastic Agents / Q000494:pharmacology; D002766:Cholecystokinin / Q000378:metabolism*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D016473:Gallbladder Emptying / Q000187:drug effects*; D005744:Gastric Acid / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007260:Infusion Pumps; D008297:Male; D010919:Placebos; D013004:Somatostatin / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D005755:Gastrins; D010919:Placebos; C051458:vapreotide; D013004:Somatostatin; D002766:Cholecystokinin