**Core Concept**
Prolactin is a hormone produced by the anterior pituitary gland, playing a crucial role in lactation, reproductive functions, and overall endocrine balance. The regulation of prolactin involves a delicate interplay between inhibitory and stimulatory mechanisms.

**Why the Correct Answer is Right**
Prolactin levels are typically inhibited by the hypothalamic hormone dopamine, which acts on the D2 receptors in the pituitary gland. Conversely, stress, certain medications, and conditions can stimulate prolactin release. However, some factors do not increase prolactin levels but instead have a neutral or even inhibitory effect. For instance, estrogen and progesterone, although crucial for reproductive functions, do not directly stimulate prolactin release.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because stress can indeed increase prolactin levels by releasing cortisol, which stimulates the hypothalamic-pituitary-adrenal axis and leads to increased prolactin release.
**Option B:** Incorrect because certain medications like phenothiazines and metoclopramide can block dopamine receptors, leading to increased prolactin levels.
**Option C:** Incorrect because sleep deprivation and fatigue can stimulate stress hormones, including cortisol, which in turn increases prolactin release.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that prolactin levels can be elevated in various conditions, including pregnancy, stress, and certain medications. However, factors like estrogen and progesterone do not directly stimulate prolactin release, making them key points to differentiate in clinical practice.

**Correct Answer:** D. Estrogen and progesterone