Is prolactin a dopamine antagonist?
Is prolactin a dopamine antagonist?
Prolactin is a unique anterior pituitary hormone, as its release is under tonic inhibitory control by dopamine.
What is prolactin antagonist?
Prolactin inhibitors are agents that inhibit the production of prolactin, a hormone that stimulates milk production after childbirth. In both sexes, excessive secretion of prolactin (hyperprolactinemia) can give rise to abnormal production of milk (galactorrhea).
How does dopamine inhibit prolactin?
Dopamine (DA) holds a predominant role in the regulation of prolactin (PRL) secretion. It accomplishes this by binding to D2 receptors expressed on the cell membrane of the lactotroph, activation of which results in a reduction of PRL exocytosis and gene expression by a variety of intracellular signalling mechanisms.
What drugs inhibit prolactin?
Bromocriptine, a D2 receptor agonist, and the most commonly used prolactin inhibitor.
How does dopamine inhibit?
After being released from the neuron, dopamine can interact with autoreceptors and inhibits further release of the neurotransmitter. The elevated intracellular dopamine also suppresses TH activity by binding to its pterin cofactor and decreasing the rate of synthesis.
Does estrogen inhibit prolactin?
Estrogen and progesterone inhibit the stimulatory effects of prolactin on milk production. The abrupt drop of estrogen and progesterone levels following delivery allow prolactin—which temporarily remains high—to induce lactation.
Is bromocriptine a dopamine agonist?
Bromocriptine is in a class of medications called dopamine receptor agonists. It treats hyperprolactinemia by decreasing the amount of prolactin in the body. It treats acromegaly by decreasing the amount of growth hormone in the body. It treats Parkinson’s disease by stimulating the nerves that control movement.
Why do dopamine antagonists increase prolactin?
Because dopamine is involved in prolactin production, domperidone may increase prolactin levels resulting in galactorrhea or gynecomastia. There may be an impact on fertility as a result of domperidone’s effect on prolactin levels.
What is the relationship between dopamine and prolactin?
One of the main regulators of the production of prolactin from the pituitary gland is the hormone called dopamine, which is produced by the hypothalamus, the part of the brain directly above the pituitary gland. Dopamine restrains prolactin production, so the more dopamine there is, the less prolactin is released.
Which antipsychotics are dopamine antagonists?
Dopamine Antagonists
| Drug | Drug Description |
|---|---|
| Molindone | An antipsychotic used to treat schizophrenia. |
| Sertindole | An atypical antipsychotic indicated in the treatment of schizophrenia. |
| Alizapride | A dopamine antagonist used to prevent nausea and vomiting associated with medical procedures, surgeries, and cancer therapies. |
What inhibits dopamine receptors?
First generation antipsychotics are used to treat schizophrenia and are often accompanied by extrapyramidal side effects. They inhibit dopaminergic neurotransmission in the brain by blocking about 72% of the D2 dopamine receptors. They can also block noradrenergic, cholinergic, and histaminergic activity.
How does dopamine affect prolactin?
Dopamine binds to the dopamine D2 receptors on the surface of the lactotroph, which diminish intracellular cyclic AMP (cAMP), consequently decreasing prolactin secretion. Any factor disrupting the delivery of dopamine to the anterior pituitary or disturbing signal transduction may result in hyperprolactinemia.
What is the mechanism of action of prolactin?
Prolactin is a unique anterior pituitary hormone, as its release is under tonic inhibitory control by dopamine. Dopamine is delivered to the adenohypophysis from the hypothalamus via the hypothalamic-hypophyseal portal system.
How does metaclopramide affect prolactin levels?
The dopamine antagonist metaclopramide abolishes the pulsatility of prolactin release and increases serum prolactin levels (19,20,24). Interference with dopamine release from the hypothalamus to the pituitary routinely raises serum prolactin levels.
What is the molecular biology of hyper-prolactinemia and lactotroph adenomas?
The molecular biology of idiopathic hyper-prolactinemia and lactotroph adenomas remains uncertain, but an area of research interest. Dopamine D2 receptors are localized to lactotrophs in the adenohypophysis and, when coupled to dopamine, maintain inhibition of prolactin secretion.
