## **Core Concept**
Prolactin is a hormone produced by the pituitary gland, specifically by the lactotroph cells in the anterior lobe. Its primary function is to stimulate lactation in postpartum women. The regulation and synthesis of prolactin involve complex interactions between various hypothalamic and pituitary factors.

## **Why the Correct Answer is Right**
The correct answer, **D. Anterior pituitary**, is right because prolactin is synthesized and secreted by the lactotroph cells located in the anterior lobe of the pituitary gland. The anterior pituitary gland is responsible for producing several hormones under the influence of releasing and inhibiting hormones from the hypothalamus. Prolactin secretion is primarily under tonic inhibitory control by dopamine from the hypothalamus.

## **Why Each Wrong Option is Incorrect**
- **Option A:** The posterior pituitary is involved in the storage and release of hormones produced by the hypothalamus, such as oxytocin and vasopressin, but not in the synthesis of prolactin.
- **Option B:** The intermediate lobe of the pituitary gland is not typically recognized as a distinct functional part in humans and is not primarily associated with prolactin synthesis.
- **Option C:** The hypothalamus produces factors that regulate prolactin secretion (like dopamine), but it does not synthesize prolactin itself.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that hyperprolactinemia, or elevated prolactin levels, can result from various conditions including prolactinoma (a type of pituitary adenoma), thyroid dysfunction, renal failure, and certain medications. This condition can lead to symptoms such as galactorrhea, amenorrhea, and infertility.

## **Correct Answer:** D. Anterior pituitary.