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Physiological Reviews Oct 2000Prolactin is a protein hormone of the anterior pituitary gland that was originally named for its ability to promote lactation in response to the suckling stimulus of... (Review)
Review
Prolactin is a protein hormone of the anterior pituitary gland that was originally named for its ability to promote lactation in response to the suckling stimulus of hungry young mammals. We now know that prolactin is not as simple as originally described. Indeed, chemically, prolactin appears in a multiplicity of posttranslational forms ranging from size variants to chemical modifications such as phosphorylation or glycosylation. It is not only synthesized in the pituitary gland, as originally described, but also within the central nervous system, the immune system, the uterus and its associated tissues of conception, and even the mammary gland itself. Moreover, its biological actions are not limited solely to reproduction because it has been shown to control a variety of behaviors and even play a role in homeostasis. Prolactin-releasing stimuli not only include the nursing stimulus, but light, audition, olfaction, and stress can serve a stimulatory role. Finally, although it is well known that dopamine of hypothalamic origin provides inhibitory control over the secretion of prolactin, other factors within the brain, pituitary gland, and peripheral organs have been shown to inhibit or stimulate prolactin secretion as well. It is the purpose of this review to provide a comprehensive survey of our current understanding of prolactin's function and its regulation and to expose some of the controversies still existing.
Topics: Alternative Splicing; Animals; Breast; Cell Line; Circadian Rhythm; Female; Homeostasis; Humans; Lymphocytes; Organ Specificity; Pituitary Gland, Anterior; Pregnancy; Prolactin; Protein Isoforms; Receptors, Prolactin; Reproduction; Signal Transduction; Structure-Activity Relationship
PubMed: 11015620
DOI: 10.1152/physrev.2000.80.4.1523 -
Hormones and Behavior May 2019Parental care is a critical component of reproductive success for many species, but especially for birds that have high rates of parental care. While ample studies have... (Review)
Review
Parental care is a critical component of reproductive success for many species, but especially for birds that have high rates of parental care. While ample studies have shown strong, positive correlational relationships between the hormone prolactin and parental care in birds, few studies in a limited number of avian species have performed the causal experiments necessary to elucidate the exact roles of prolactin during these behaviors. Additionally, how prolactin acts in the brain to affect parental behaviors is still virtually unknown with the exception of a small number of studies in very few species. Here, I review what is currently known about prolactin and avian parental care, propose a new hypothesis for prolactin's role in avian parental care, and highlight the gaps in our current understanding of prolactin's role in parental care.
Topics: Animals; Birds; Female; Male; Maternal Behavior; Nesting Behavior; Paternal Behavior; Prolactin; Reproduction
PubMed: 30802443
DOI: 10.1016/j.yhbeh.2019.02.012 -
Endocrine Aug 2017Prolactin is a peptide hormone mainly synthetized and secreted by the anterior pituitary gland, but also by extrapituitary tissues, such as mammary gland, decidua,... (Review)
Review
INTRODUCTION
Prolactin is a peptide hormone mainly synthetized and secreted by the anterior pituitary gland, but also by extrapituitary tissues, such as mammary gland, decidua, prostate, skin, and possibly the brain. Similarly, prolactin receptor is expressed in the pituitary gland, many peripheral tissues, and in contrast to prolactin, its receptor has been consistently detected in several brain regions, such as cerebral cortex, olfactory bulb, hypothalamus, hippocampus, amygdala, among others. Classically, prolactin function has been related to the stimulation of lactogenesis and galactopoiesis, however, it is well known that prolactin induces a wide range of functions in different brain areas.
PURPOSE
The aim of this review is to summarize recent reports on prolactin and prolactin receptor synthesis and localization, as well as recapitulate both the classic functions attributed to this hormone in the brain and the recently described functions such as neurogenesis, neurodevelopment, sleep, learning and memory, and neuroprotection.
CONCLUSION
The distribution and putative expression of prolactin and its receptors in several neuronal tissues suggests that this hormone has pleiotropic functions in the brain.
Topics: Animals; Brain Chemistry; Humans; Prolactin; Receptors, Prolactin
PubMed: 28634745
DOI: 10.1007/s12020-017-1346-x -
Molecular and Cellular Biochemistry May 2022Prolactin (PRL) is a peptide hormone secreted from anterior pituitary involved in milk production in the females and regulation of sex drive in both sexes. PRL has... (Review)
Review
Prolactin (PRL) is a peptide hormone secreted from anterior pituitary involved in milk production in the females and regulation of sex drive in both sexes. PRL has pro-inflammatory and anti-inflammatory functions. High PRL serum level or hyperprolactinemia is associated with different viral infections. In coronavirus disease 2019 (Covid-19), which caused by positive-sense single-strand RNA virus known as severe acute respiratory distress syndrome coronavirus type 2 (SARS-CoV-2), PRL serum level is increased. PRL in Covid-19 may exacerbate the underlying inflammatory status by induction release of pro-inflammatory cytokines. However, PRL through its anti-inflammatory effects may reduce the hyperinflammatory status in Covid-19. The underlying mechanism of increasing PRL in Covid-19 is poorly understood. Therefore, in this review we try to find the potential anti-inflammatory or pro-inflammatory role of PRL in Covid-19. As well, this review was aimed to discuss the underlying causes and mechanisms for Covid-19-induced hyperprolactinemia.
Topics: COVID-19; Cytokines; Female; Humans; Hyperprolactinemia; Male; Prolactin; SARS-CoV-2
PubMed: 35147901
DOI: 10.1007/s11010-022-04381-9 -
Clinical Obstetrics and Gynecology Jun 1980The principal physiologic effect of PRL in human females is the initiation of lactation. The cellular events leading to actual secretion of breast milk are reasonably... (Review)
Review
The principal physiologic effect of PRL in human females is the initiation of lactation. The cellular events leading to actual secretion of breast milk are reasonably well defined in the experimental animal. Other than the direct effects on breast tissue in pregnancy, prolactin's role at puberty, during the menstrual cycle, and in pregnancy is poorly defined at present. Although there are large quantities of PRL in amniotic fluid the physiologic role is unknown. There is evidence for an osmoregulatory role of PRL in the amniotic fluid, and a very questionable role for PRL in fetal lung maturation. Overall, much more investigation is warranted to define more clearly the effects of PRL in reproductive physiology.
Topics: Amniotic Fluid; Animals; Breast; Corpus Luteum; Female; Humans; Labor, Obstetric; Lactation; Menstruation; Pregnancy; Prolactin
PubMed: 6994965
DOI: 10.1097/00003081-198006000-00005 -
Archives of Endocrinology and Metabolism 2016Prolactin is best known for its effects of stimulating mammary gland development and lactogenesis. However, prolactin is a pleiotropic hormone that is able to affect... (Review)
Review
Prolactin is best known for its effects of stimulating mammary gland development and lactogenesis. However, prolactin is a pleiotropic hormone that is able to affect several physiological functions, including fertility. Prolactin receptors (PRLRs) are widely expressed in several tissues, including several brain regions and reproductive tract organs. Upon activation, PRLRs may exert prolactin's functions through several signaling pathways, although the recruitment of the signal transducer and activator of transcription 5 causes most of the known effects of prolactin. Pathological hyperprolactinemia is mainly due to the presence of a prolactinoma or pharmacological effects induced by drugs that interact with the dopamine system. Notably, hyperprolactinemia is a frequent cause of reproductive dysfunction and may lead to infertility in males and females. Recently, several studies have indicated that prolactin may modulate the reproductive axis by acting on specific populations of hypothalamic neurons that express the Kiss1 gene. The Kiss1 gene encodes neuropeptides known as kisspeptins, which are powerful activators of gonadotropin-releasing hormone neurons. In the present review, we will summarize the current knowledge about prolactin's actions on reproduction. Among other aspects, we will discuss whether the interaction between prolactin and the Kiss1-expressing neurons can affect reproduction and how kisspeptins may become a novel therapeutic approach to treat prolactin-induced infertility.
Topics: Female; Humans; Hyperprolactinemia; Hypothalamus; Infertility; Kisspeptins; Male; Prolactin; Receptors, Prolactin; Reproduction; Sex Factors; Signal Transduction
PubMed: 27901187
DOI: 10.1590/2359-3997000000230 -
Canadian Journal of Physiology and... Jun 2007Prolactin has been shown to stimulate intestinal calcium absorption, increase bone turnover, and reduce renal calcium excretion. The small intestine, which is the sole... (Review)
Review
Prolactin has been shown to stimulate intestinal calcium absorption, increase bone turnover, and reduce renal calcium excretion. The small intestine, which is the sole organ supplying new calcium to the body, intensely expresses mRNAs and proteins of prolactin receptors, especially in the duodenum and jejunum, indicating the intestine as a target tissue of prolactin. A number of investigations show that prolactin is able to stimulate the intestinal calcium transport both in vitro and in vivo, whereas bromocriptine, which inhibits pituitary prolactin secretion, antagonizes its actions. In female rats, acute and long-term exposure to high prolactin levels significantly enhances the (i) transcellular active, (ii) solvent drag-induced, and (iii) passive calcium transport occurring in the small intestine. These effects are seen not only in pregnant and lactating animals, but are also observed in non-pregnant and non-lactating animals. Interestingly, young animals are more responsive to prolactin than adults. Prolactin-enhanced calcium absorption gradually diminishes with age, thus suggesting it has an age-dependent mode of action. Although prolactin's effects on calcium absorption are not directly vitamin D-dependent; a certain level of circulating vitamin D may be required for the basal expression of genes related to calcium transport. The aforementioned body of evidence supports the hypothesis that prolactin acts as a regulator of calcium homeostasis by controlling the intestinal calcium absorption. Cellular and molecular signal transductions of prolactin in the enterocytes are largely unknown, however, and still require investigation.
Topics: Animals; Biological Transport; Calcium; Enterocytes; Homeostasis; Humans; Models, Biological; Prolactin
PubMed: 17823618
DOI: 10.1139/y07-041 -
Lupus 2001The presence of extra-pituitary prolactin and its cognitive receptors in the hematopoietic micro-environment raises the question of whether prolactin plays a role in... (Review)
Review
The presence of extra-pituitary prolactin and its cognitive receptors in the hematopoietic micro-environment raises the question of whether prolactin plays a role in lympho-hematopoiesis and under what conditions. Current studies suggest that endogenous prolactin does not play a significant role under normal steady-state conditions. Rather, prolactin has been implicated as a 'stress hormone', functioning to restore hematopoietic homeostasis under conditions of dysregulation. The stress response of prolactin as well as its complex relationship with other hormones and factors has resulted in conflicting reports in the literature regarding prolactin's role in lympho-hematopoiesis. A review of this literature is provided as well as discussion of conditions under which lymphohematopoietic activity of prolactin may be evident.
Topics: Animals; Cell Differentiation; Hematopoiesis; Hematopoietic Stem Cells; Humans; Prolactin; Receptors, Prolactin
PubMed: 11721696
DOI: 10.1191/096120301717164930 -
Horumon To Rinsho. Clinical... Mar 1973
Review
Topics: Animals; Cross Reactions; Female; Humans; Iodine Isotopes; Methods; Mice; Prolactin; Rabbits; Radioimmunoassay
PubMed: 4581692
DOI: No ID Found -
Canadian Journal of Physiology and... Dec 2000The amino acid sequence of newt (Cynops pyrrhogaster) prolactin deduced from the nucleotide sequence of its cDNA showed a relatively high homology with sequences of... (Review)
Review
The amino acid sequence of newt (Cynops pyrrhogaster) prolactin deduced from the nucleotide sequence of its cDNA showed a relatively high homology with sequences of chicken and sea turtle prolactins as well as with those of anuran prolactins. Cynops prolactin receptor transcripts were detected in various tissues and organs, suggesting that prolactin plays multiple roles in urodeles. Urodele prolactin was purified from the pituitaries of C. pyrrhogaster. Antiserum against this prolactin was used for radioimmunoassay of plasma prolactin and immunoneutralization experiments. Endogenous prolactin was shown to induce migration to water, courtship behavior, and cessation of spermatocytogenesis in the Cynops newt. The hormone was found to be involved in the development of cloacal glands such as the lateral and abdominal glands, growth of the tail and Mauthner neurons, secretion of oviducal jelly, and enhanced synthesis of a female attracting pheromone (sodefrin), and responsiveness of the olfactory epithelium to sodefrin. In most of these cases, prolactin was found to act synergistically or antagonistically with sex steroids. We also discovered that hypersecretion of prolactin in the newts subjected to cold temperature was induced by hypothalamic stimulation rather than release from hypothalamic inhibition.
Topics: Amino Acid Sequence; Animals; Cloning, Molecular; Female; Male; Molecular Sequence Data; Oviducts; Pheromones; Prolactin; Receptors, Prolactin; Reproduction; Salamandridae; Sexual Behavior, Animal; Spermatogenesis
PubMed: 11149387
DOI: No ID Found