A 42-year-old man presents with recurrent RUQ pain for 2 years. A sonogram is negative for gallstones, and the CBD is normal. An upper GI endoscopy is also normal, and there is no peptic ulcer disease. Biliary dyskinesia is suspected, and the patient undergoes further evaluation. Which of the following will stimulate contraction of the gallbladder?

A cholecystokinin stimulated HIDA scan should be performed. Failure of the gallbladder to contract after stimulation by cholecystokinin may suggest dyskinesia. This is an indication for cholecystectomy, even though stones are not demonstrated. Secretin is the duodenal hormone that stimulates exocrine pancreatic secretion. Gastrin, released mainly from the antrum, increases gastric acid secretion that is high in bicarbonate and electrolytes.