Which of the following hormones is not secreted by duodenum to inhibit the gastric motility?

Options

A. GIP
B. Enterogastrone
C. Secretin
D. Enterokinase

Answer

To solve the question "Which of the following hormones is not secreted by the duodenum to inhibit gastric motility?", we will analyze each option provided and determine whether it is secreted by the duodenum and if it plays a role in inhibiting gastric motility.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which hormone is NOT secreted by the duodenum to inhibit gastric motility. We need to evaluate the options given.

2. **Reviewing the Options**:
- **Option 1: GIP (Gastric Inhibitory Peptide)**:
- GIP is indeed secreted by the duodenum and is known for its role in inhibiting gastric motility.
- **Conclusion**: GIP is secreted by the duodenum.

- **Option 2: Enterogastrone**:
- Enterogastrone is a hormone that is also secreted by the duodenum. It helps to inhibit gastric motility, especially in response to the presence of fats in the intestine.
- **Conclusion**: Enterogastrone is secreted by the duodenum.

- **Option 3: Secretin**:
- Secretin is another hormone that is secreted by the duodenum. It primarily regulates water homeostasis and also has a role in inhibiting gastric motility.
- **Conclusion**: Secretin is secreted by the duodenum.

- **Option 4: Enterokinase**:
- Enterokinase is not a hormone; it is an enzyme that activates trypsinogen to trypsin. It is secreted by the duodenum but does not have a role in inhibiting gastric motility.
- **Conclusion**: Enterokinase is NOT secreted by the duodenum to inhibit gastric motility.

3. **Final Answer**: Based on the analysis, the hormone that is NOT secreted by the duodenum to inhibit gastric motility is **Option 4: Enterokinase**.