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In general, dopamine inhibits prolactin [14] but this process has feedback mechanisms. [15] Elevated levels of prolactin decrease the levels of sex hormones—estrogen in women and testosterone in men. [16] The effects of mildly elevated levels of prolactin are much more variable, in women, substantially increasing or decreasing estrogen levels.
Prolactin secretion in the pituitary lactrotroph cells is normally suppressed by the brain chemical dopamine, which binds to dopamine receptors. Drugs that block the effects of dopamine at the pituitary or deplete dopamine stores in the brain may cause the pituitary to secrete excess prolactin without an inhibitory effect.
The arcuate nucleus and the periventricular nucleus of the hypothalamus have dopamine neurons that form an important projection—the tuberoinfundibular pathway which goes to the pituitary gland, where it influences the secretion of the hormone prolactin. [50] Dopamine is the primary neuroendocrine inhibitor of the secretion of prolactin from ...
Dopamine released at this site inhibits the secretion of prolactin from anterior pituitary gland lactotrophs by binding to dopamine receptor D2. Some antipsychotic drugs block dopamine in the tuberoinfundibular pathway, which can cause an increase in the amount of prolactin in the blood (hyperprolactinemia).
Dopamine released from their nerve endings at the median eminence is transported to the anterior pituitary gland, where it regulates the secretion of prolactin. Dopamine inhibits prolactin secretion, so when the TIDA neurons are inhibited, there is increased secretion of prolactin, which stimulates lactogenesis (milk production).
A prolactin cell (also known as a lactotropic cell, epsilon acidophil, lactotrope, lactotroph, mammatroph, mammotroph) is a cell in the anterior pituitary which produces prolactin (a peptide hormone) in response to hormonal signals including dopamine (which is inhibitory), thyrotropin-releasing hormone and estrogen (especially during pregnancy), which are stimulatory.
Prolactin inhibitors are mainly used to treat hyperprolactinemia (high prolactin levels). [1] Agonists of the dopamine D 2 receptor such as bromocriptine and cabergoline are able to strongly suppress pituitary prolactin secretion and thereby decrease circulating prolactin levels, and so are most commonly used as prolactin inhibitors. [1]
Hypoprolactinemia can result from autoimmune disease, [2] hypopituitarism, [1] growth hormone deficiency, [2] hypothyroidism, [2] excessive dopamine action in the tuberoinfundibular pathway and/or the anterior pituitary, and ingestion of drugs that activate the D 2 receptor, such as direct D 2 receptor agonists like bromocriptine and pergolide, and indirect D 2 receptor activators like ...