What is the target/action site of cholecystokinin (CCK)?

Explanation

**Step-by-Step Text Solution:**

1. **Identify the Hormone**: The question asks about cholecystokinin (CCK), which is a peptide hormone.

2. **Source of CCK**: CCK is secreted by the endocrine cells of the gastrointestinal tract, primarily by the I cells located in the small intestine.

3. **Target Sites**: CCK has two main target/action sites:
- **Pancreas**: CCK stimulates the pancreas to secrete pancreatic juice, which contains digestive enzymes essential for food digestion.
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