A prolactin modulator is a drug which affects the

hypothalamic–pituitary–prolactin axis The hypothalamic–pituitary–prolactin axis (HPP axis), also known as the hypothalamic–pituitary–mammary axis or hypothalamic–pituitary–breast axis, is a hypothalamic–pituitary axis which includes the secretion of prolactin (PRL; lut ...

(HPP axis) by modulating the

secretion Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical mec ...

of the

pituitary hormone The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus control much of th ...

prolactin Prolactin (PRL), also known as lactotropin and mammotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secr ...

from the

anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

pituitary gland The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the human brain, brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus contr ...

. ''Prolactin inhibitors'' suppress and ''prolactin releasers'' induce the secretion of prolactin, respectively.

Prolactin inhibitors

Prolactin inhibitors are mainly used to treat

hyperprolactinemia Hyperprolactinaemia (also spelled hyperprolactinemia) is a condition characterized by abnormally high levels of prolactin in the blood. In women, normal prolactin levels average to about 13 ng/mL, while in men, they average 5 ng/mL. ...

(high prolactin levels).

Agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

s of the

dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...

D₂ receptor such as

bromocriptine Bromocriptine, originally marketed as Parlodel and subsequently under many brand names, is an ergoline derivative and dopamine agonist that is used in the treatment of pituitary tumors, Parkinson's disease, hyperprolactinaemia, neuroleptic malig ...

and

cabergoline Cabergoline, sold under the brand name Dostinex among others, is a dopaminergic medication used in the treatment of high prolactin levels, prolactinomas, Parkinson's disease, and for other indications. It is taken by mouth. Cabergoline is an ...

are able to strongly suppress pituitary prolactin secretion and thereby decrease circulating prolactin levels, and so are most commonly used as prolactin inhibitors. D₂ receptor agonists that are described as prolactin inhibitors include the approved medications

lisuride Lisuride, sold under the brand name Dopergin among others, is a monoaminergic medication of the ergoline family which is used in the treatment of Parkinson's disease, migraine, and high prolactin levels. It is taken by mouth. Side effects of l ...

metergoline Metergoline (, ), also known as methergoline and sold under the brand names Contralac (veterinary) and Liserdol (clinical), is a monoaminergic medication of the ergoline group which is used as a prolactin inhibitor in the treatment of hyperprola ...

pergolide Pergolide, sold under the brand name Permax and Prascend (veterinary) among others, is an ergoline-based dopamine receptor agonist used in some countries for the treatment of Parkinson's disease. Parkinson's disease is associated with reduced do ...

quinagolide Quinagolide (, ), sold under the brand name Norprolac, is a binding selectivity, selective dopamine receptor, dopamine D2 receptor, D2 receptor agonist which is used to manage hyperprolactinemia. It has also been found to be effective in the trea ...

, and

terguride Terguride (, ), sold under the brand name Teluron, is a serotonin receptor antagonist and dopamine receptor agonist of the ergoline family. It is approved for and used as a prolactin inhibitor in the treatment of hyperprolactinemia (high prolact ...

and the never-marketed agent

lergotrile Lergotrile (, ) is an ergoline derivative which acts as a dopamine receptor agonist. It was developed for the treatment of Parkinson's disease, but failed in clinical trials due to liver toxicity Hepatotoxicity (from ''hepatic toxicity'') imp ...

. Other dopamine agonists and dopaminergic agents, for instance

levodopa Levodopa, also known as L-DOPA and sold under many brand names, is a dopaminergic medication which is used in the treatment of Parkinson's disease (PD) and certain other conditions like dopamine-responsive dystonia and restless legs syndrome. ...

(L-DOPA), can also inhibit prolactin secretion.

Antiestrogen Antiestrogens, also known as estrogen antagonists or estrogen blockers, are a class of drugs which prevent estrogens like estradiol from mediating their biological effects in the body. They act by blocking the estrogen receptor (ER) and/or inh ...

s such as

aromatase inhibitor Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exo ...

s and analogues are also able to inhibit the secretion of prolactin, though not nearly as robustly as D₂ receptor agonists, and as such, they are not usually used as prolactin inhibitors.

Prolactin releasers

Whereas D₂ receptor agonists suppress prolactin secretion, dopamine D₂ receptor

antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.domperidone Domperidone, sold under the brand name Motilium among others, is a dopamine antagonist medication which is used to treat nausea and vomiting and certain gastrointestinal problems like gastroparesis (delayed gastric emptying). It raises the ...

and

metoclopramide Metoclopramide is a medication used to treat nausea, vomiting, gastroparesis, and gastroesophageal reflux disease. It is also used to treat migraine headaches. Common side effects include feeling tired, diarrhea, akathisia, and tardive dyski ...

have the opposite effect, strongly inducing the pituitary secretion of prolactin, and are sometimes used as prolactin releasers, for instance to correct

hypoprolactinemia Hypoprolactinemia is a medical condition characterized by a deficiency in the serum levels of the hypothalamic-pituitary hormone prolactin. Signs and symptoms Hypoprolactinemia is associated with ovarian dysfunction in women, and, in men, meta ...

(low prolactin levels) in the treatment of lactation failure. When such drugs are used not for the purpose of inducing prolactin secretion, increased prolactin levels may be unwanted, and can result in various

side effect In medicine, a side effect is an effect of the use of a medicinal drug or other treatment, usually adverse but sometimes beneficial, that is unintended. Herbal and traditional medicines also have side effects. A drug or procedure usually use ...

s including

mammoplasia Mammoplasia is the normal or spontaneous enlargement of human breasts. Mammoplasia occurs normally during puberty and pregnancy in women, as well as during certain periods of the menstrual cycle. When it occurs in males, it is called gynecomasti ...

(breast enlargement),

mastodynia Breast pain is the symptom of discomfort in either one or both breasts. Pain in both breasts is often described as ''breast tenderness'', is usually associated with the menstrual period and is not serious. Pain that involves only one part of a b ...

(breast pain/tenderness),

galactorrhea Galactorrhea ( also spelled galactorrhoea) ( galacto- + -rrhea) or lactorrhea ( lacto- + -rrhea) is the spontaneous flow of milk from the breast, unassociated with childbirth or nursing. Galactorrhea is reported to occur in 5–32% of females. ...

(inappropriate or excessive milk production/secretion),

gynecomastia Gynecomastia (also spelled gynaecomastia) is the non-cancerous enlargement of one or both breasts in men due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse (10 Novemb ...

(

breast development Breast development, also known as mammogenesis, is a complex biological process in primates that takes place throughout a female's life. It occurs across several phases, including prenatal development, puberty, and pregnancy. At menopause, breas ...

in males),

hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...

(low

sex hormone Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effects a ...

levels),

amenorrhea Amenorrhea or amenorrhoea is the absence of a menstrual period in a female organism who has reached reproductive age. Physiological states of amenorrhoea are most commonly seen during pregnancy and lactation (breastfeeding). In humans, it is wher ...

(cessation of

menstrual cycle The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eg ...

s), reversible

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

, and

sexual dysfunction Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction ...

. Indirect

dopaminergic agent Dopaminergic means "related to dopamine" (literally, "working on dopamine"), a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain. Dopaminergic brain pathways facilitate dopamine-related ...

s such as

can also suppress prolactin levels. Other prolactin releasers besides D₂ receptor antagonists include

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

s (e.g.,

estradiol Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible ...

progestogen Progestogens, also sometimes written progestins, progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestoge ...

s (e.g.,

progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...

thyrotropin-releasing hormone Thyrotropin-releasing hormone (TRH) is a hypophysiotropic hormone produced by neurons in the hypothalamus that stimulates the release of thyroid-stimulating hormone (TSH) as well as prolactin from the anterior pituitary. TRH has been used ...

and analogues (e.g.,

protirelin Thyrotropin-releasing hormone (TRH) is a hypophysiotropic hormone produced by neurons in the hypothalamus that stimulates the release of thyroid-stimulating hormone (TSH) as well as prolactin from the anterior pituitary. TRH has been used c ...

, taltirelin), and

vasoactive intestinal peptide Vasoactive intestinal peptide, also known as vasoactive intestinal polypeptide or VIP, is a peptide hormone that is vasoactive in the intestine. VIP is a peptide of 28 amino acid residue (chemistry), residues that belongs to a Secretin family, glu ...

Serotonergic agent A serotonergic substance, medication, or receptor protein is one that affects neurotransmission pathways that involve serotonin, as follows: * Serotonergic drugs ** Serotonin receptor agonists ** Serotonin receptor antagonists ** Serotonin reupta ...

s such as

serotonin precursor Monoamine precursors are precursors of monoamines and monoamine neurotransmitters in the body. The amino acids L-tryptophan and L-5-hydroxytryptophan (5-HTP; oxitriptan) are precursors of serotonin and melatonin, while the amino acids L-phenyla ...

s (e.g.,

tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromat ...

serotonin reuptake inhibitor A serotonin reuptake inhibitor (SRI) is a type of drug which acts as a reuptake inhibitor of the neurotransmitter serotonin (5-hydroxytryptamine, or 5-HT) by blocking the drug action, action of the serotonin transporter (SERT). This in turn lea ...

serotonin releasing agent A serotonin releasing agent (SRA) is a type of drug that induces the release of serotonin into the neuronal synaptic cleft. A selective serotonin releasing agent (SSRA) is an SRA with less significant or no efficacy in producing neurotransmitter ...

s (e.g.,

fenfluramine Fenfluramine, sold under the brand name Fintepla, is a serotonergic medication used for the treatment of seizures associated with Dravet syndrome and Lennox–Gastaut syndrome. It was formerly used as an appetite suppressant in the treat ...

MDMA 3,4-Methylenedioxymethamphetamine (MDMA), commonly known as ecstasy (tablet form), and molly (crystal form), is an empathogen–entactogenic drug with stimulant and minor Psychedelic drug, psychedelic properties. In studies, it has been used ...

monoamine oxidase inhibitor Monoamine oxidase inhibitors (MAOIs) are a drug class, class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressa ...

s, and

serotonin receptor agonist A serotonin receptor agonist is an agonist of one or more serotonin receptors. They activate serotonin receptors in a manner similar to that of serotonin (5-hydroxytryptamine; 5-HT), a neurotransmitter and hormone and the endogenous ligand of t ...

s have also been associated with increases in prolactin levels.

References

External links

* {{Breastfeeding Breastfeeding