Prolactin is secreted by
**Core Concept**
Prolactin is a hormone produced by the anterior pituitary gland, playing a crucial role in lactation, reproductive functions, and immune system regulation. Its secretion is primarily under the inhibitory control of dopamine.
**Why the Correct Answer is Right**
The anterior pituitary gland is a crucial endocrine organ that produces several hormones, including prolactin, growth hormone, and thyroid-stimulating hormone. Prolactin secretion is primarily regulated by the hypothalamic-pituitary axis, where dopamine from the hypothalamus inhibits the release of prolactin from the anterior pituitary gland. When dopamine levels decrease, prolactin secretion increases. This complex interplay between the hypothalamus and the anterior pituitary gland is essential for maintaining normal prolactin levels.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect as it does not specify the correct gland responsible for prolactin secretion. The posterior pituitary gland primarily stores and releases antidiuretic hormone and oxytocin.
**Option B:**
This option is incorrect as it suggests a different gland responsible for prolactin secretion. The thyroid gland produces thyroid hormones, which regulate metabolism, growth, and development, but it does not produce prolactin.
**Option C:**
This option is incorrect as it suggests a different gland responsible for prolactin secretion. The adrenal gland produces hormones such as cortisol and aldosterone, but it does not produce prolactin.
**Clinical Pearl / High-Yield Fact**
Prolactin levels are often elevated in conditions such as hypothyroidism, sleep disorders, and certain types of tumors, including pituitary adenomas. It is essential to consider these conditions when interpreting prolactin levels in patients.
**Correct Answer:** D. The anterior pituitary gland.