Which of the following belongs to local hormones? A. Gastrin B. Atrial natriuretic factor C. Prostaglandins D. All of the above

The correct answer is D. All of the above.

Local hormones are substances that act locally within the tissues or cells where they are produced, rather than being transported through the bloodstream to distant target organs. Gastrin, atrial natriuretic factor (ANF), and prostaglandins are examples of local hormones.

Gastrin is a hormone that is released by the stomach lining and plays a role in regulating gastric acid secretion and promoting digestion.

Atrial natriuretic factor (ANF) is a hormone released by the heart, specifically the atria, in response to increased blood volume and pressure. It helps regulate blood pressure and fluid balance by promoting sodium and water excretion by the kidneys.

Prostaglandins are a group of lipid compounds that are produced by various tissues throughout the body. They have a wide range of physiological functions, including regulation of inflammation, blood flow, and uterine contractions.

Therefore, all of the options mentioned (A. Gastrin, B. Atrial natriuretic factor, C. Prostaglandins) belong to the category of local hormones.