With regard to the control of pancreatic exocrine function, which of the following statement(s) is/are correct?

a. Cholecystokinin, a hormone released from the duodenal mucosa, is the predominant stimulus for pancreatic enzyme secretion

c. Secretin is released from the duodenum upon mucosal acidification and stimulates pancreatic bicarbonate secretion

d. Acetylcholine, released from pancreatic nerves, stimulates enzyme secretion

Enzyme secretion is regulated primarily through hormonal and neural factors. The enteric hormone cholecystokinin, released from endocrine cells in the duodenal mucosa, is the predominant regulator and stimulates acinar cells through specific membrane-bound receptors. Acetylcholine strongly stimulates acinar cells when released from postganglionic fibers of the pancreatic plexus and acts in synergy with CCK to potentiate enzyme secretion. Secretin weakly stimulates acinar cell secretion and potentiates the effect of cholecystokinin on the acinar cells. Bicarbonate is formed from carbonic acid by the enzyme carbonic anhydrase. Secretin, the major stimulant for bicarbonate secretion, is released from the duodenal mucosa in response to a duodenal luminal pH of less than 3.0. Cholecystokinin only weakly stimulates bicarbonate secretion, whereas it potentiates secretin-stimulated bicarbonate secretion. Gastrin and acetylcholine are weak stimulants of bicarbonate secretion.