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Dopamine produced by neurons in the arcuate nucleus is secreted into the hypophyseal portal system of the median eminence, which supplies the pituitary gland. [50] The prolactin cells that produce prolactin, in the absence of dopamine, secrete prolactin continuously; dopamine inhibits this secretion. [50]
Prolactin has a wide variety of effects. It stimulates the mammary glands to produce milk (): increased serum concentrations of prolactin during pregnancy cause enlargement of the mammary glands and prepare for milk production, which normally starts when levels of progesterone fall by the end of pregnancy and a suckling stimulus is present.
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.
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.
In men, high levels of prolactin can result in a number of intimate problems, including: (ED) Reduced libido. Decreased fertility. Cabergoline is a dopamine agonist. It works to reduce the amount ...
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).
Prolactin acts in a short-loop negative feedback manner to decrease its levels by stimulating the release of dopamine. Dopaminergic neurons of the arcuate also inhibit the release of gonadotropin-releasing hormone , explaining in part why lactating (or otherwise hyperprolactinemic ) women experience oligomenorrhea or amenorrhea (infrequency or ...
The dopamine neurons of the dopaminergic pathways synthesize and release the neurotransmitter dopamine. [2] [3] Enzymes tyrosine hydroxylase and dopa decarboxylase are required for dopamine synthesis. [4] These enzymes are both produced in the cell bodies of dopamine neurons. Dopamine is stored in the cytoplasm and vesicles in axon terminals.