From the Research
The correct answer is (b) stimulates pancreatic enzyme secretion. Secretin is a hormone produced by S cells in the duodenum and jejunum of the small intestine in response to acidic chyme entering from the stomach. Its primary function is to stimulate the pancreas to release bicarbonate-rich pancreatic juice, which helps neutralize the acidic content in the duodenum. While secretin does stimulate pancreatic secretions, it particularly enhances the production of bicarbonate rather than enzymes specifically, as noted in the study by 1. However, another study 2 suggests that certain substances like melatonin, leptin, or ghrelin can stimulate pancreatic enzyme secretion by activating CCK release and the duodeno-pancreatic reflex. Secretin actually inhibits gastrin secretion (not stimulates it), which leads to decreased gastric acid production (not increased), and it also has minimal effects on intestinal motility, as discussed in 3. The physiological importance of secretin lies in its role in maintaining optimal pH in the duodenum for proper digestion and absorption of nutrients, as pancreatic enzymes function best in a neutral to slightly alkaline environment. Some studies, such as 4 and 5, discuss the diagnosis and treatment of exocrine pancreatic insufficiency, but the primary function of secretin remains the stimulation of bicarbonate secretion, which indirectly supports pancreatic enzyme activity.
Key Points:
- Secretin stimulates the pancreas to release bicarbonate-rich pancreatic juice.
- It inhibits gastrin secretion, leading to decreased gastric acid production.
- Secretin has minimal effects on intestinal motility.
- Its primary function is to maintain optimal pH in the duodenum for proper digestion and absorption of nutrients.
- Other substances like melatonin, leptin, or ghrelin can stimulate pancreatic enzyme secretion through different mechanisms, as seen in 2.
Relevant Studies:
- 1: Discusses the physiology of stimulation and inhibition of pancreatic digestive enzyme secretion.
- 2: Explores the role of melatonin, leptin, and ghrelin in stimulating pancreatic enzyme secretion.
- 4: Compares pancreatic function tests with the findings of S-MRCP in patients with chronic pancreatitis.
- 3: Examines the negative feedback control of exocrine pancreatic secretion and the role of cholecystokinin and the cholinergic pathway.
- 5: Addresses the diagnosis and treatment of exocrine pancreatic insufficiency after surgery.