Sierra Acai Company
Sierra Acai Company
Open 7 Days a Week
MonaVie Independent Distributor
Distributor Training
Shop Online
Enroll Now
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
Friends
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
14-September-2008 18:02:48 - Prolactin Prolactin Identifiers Symbol PRL Entrez 5617 HUGO 9445 OMIM 176760 RefSeq NM_000948 UniProt P01236 Other data Locus Chr. 6 p22.2-p21.3 Prolactin PRL or Luteotropic hormone LTH is a peptide hormone primarily associated with lactation. In breastfeeding, the act of an infant suckling the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis, in preparation for the next feed. Oxytocin, another hormone, is also released, which triggers milk let-down. Contents 1 Production and regulation 2 Effects 3 Variance in levels 4 Structure 5 Prolactin receptor 6 Diagnostic use 6.1 Conditions causing elevated prolactin secretion 6.2 Conditions causing decreased prolactin 7 Use of breastfeeding as contraceptive 8 See also 9 References 10 External links Production and regulation Prolactin or luteotropic hormone is synthesised and secreted by lactotrope cells in the adenohypophysis anterior pituitary gland. It is also produced in other tissues including the breast and the decidua. Pituitary prolactin secretion is regulated by neuroendocrine neurons in the hypothalamus, the most important ones being the neurosecretory tuberoinfundibulum TIDA neurons of the arcuate nucleus, which secrete dopamine to act on the dopamine-2 receptors D2-R of lactotrophs, causing inhibition of prolactin secretion. Thyrotropin-releasing factor has a stimulatory effect on prolactin release. Vasoactive intestinal peptide and peptide histidine isoleucine help to regulate prolactin secretion in humans, but the functions of these hormones in birds can be quite different.1 Effects Prolactin has many effects: To stimulate the mammary glands to produce milk lactation: Increased serum concentrations of prolactin during pregnancy cause enlargement of the mammary glands of the breasts and increases the production of milk. However, the high levels of progesterone during pregnancy act directly on the breasts to stop ejection of milk. It is only when the levels of this hormone fall after childbirth that milk ejection is possible. Sometimes, newborn babies males as well as females secrete a milky substance from their nipples. This substance is commonly known as Witch's milk. This is caused by the fetus being affected by prolactin circulating in the mother just before birth, and usually stops soon after birth. To provide the body with sexual gratification after sexual acts: The hormone counteracts the effect of dopamine, which is responsible for sexual arousal. This is thought to cause the sexual refractory period.2 The amount of prolactin can be an indicator for the amount of sexual satisfaction and relaxation. Unusually high amounts are suspected to be responsible for impotence and loss of libido see hyperprolactinemia Symptoms. To stimulate proliferation of oligodendrocyte precursor cells: These cells differentiate into oligodendrocytes, the cells responsible for the formation of myelin coatings on axons in the central nervous system.3 To contribute to surfactant synthesis of the fetal lungs at the end of the pregnancy and immune tolerance of the fetus by the maternal organism during pregnancy To decrease normal levels of sex hormones - estrogen in women and testosterone in men.4 Prolactin delays hair regrowth in mice5. Variance in levels There is a diurnal as well as an ovulatory cycle in prolactin secretion. During pregnancy, high circulating concentrations of estrogen promote prolactin production. The resulting high levels of prolactin secretion cause further maturation of the mammary glands, preparing them for lactation. After childbirth, prolactin levels fall as the internal stimulus for them is removed. Sucking by the baby on the nipple then promotes further prolactin release, maintaining the ability to lactate. The sucking activates mechanoreceptors in and around the nipple. These signals are carried by nerve fibers through the spinal cord to the hypothalamus, where changes in the electrical activity of neurons that regulate the pituitary gland cause increased prolactin secretion. The suckling stimulus also triggers the release of oxytocin from the posterior pituitary gland, which triggers milk let-down: Prolactin controls milk production lactogenesis but not the milk-ejection reflex; the rise in prolactin fills the breast with milk in preparation for the next feed. In usual circumstances, in the absence of galactorrhea, lactation will cease within one or two weeks of the end of demand breastfeeding. High prolactin levels also tend to suppress the ovulatory cycle by inhibiting the secretion of both follicle-stimulating hormone FSH and gonadotropic-releasing hormone GnRH. Prolactin levels peak during REM sleep, and in the early morning. Levels can rise after exercise, meals, sexual intercourse, or minor surgical procedures.6 Structure Prolactin is a single-chain polypeptide of 199 amino acids with a molecular weight of about 24,000 daltons. Its structure is similar to that of growth hormone and placental lactogen. The molecule is folded due to the activity of three disulfide bonds. Significant heterogeneity of the molecule has been described, thus bioassays and immunoassays can give different results due to differing glycosylation, phosphorylation, sulfation, as well as degradation. The non-glycosylated form of prolactin is the dominant form of prolactin that is secreted by the pituitary gland. Little prolactin is apparently the result of removal of some amino acids, whereas big prolactin can be the product of interaction of several prolactin molecules. Pit-1 is a transcription factor that binds to the prolactin gene at several sites to allow for the production of prolactin in the pituitary gland. A key regulator of prolactin production is estrogens that enhance growth of prolactin-producing cells and stimulate prolactin production directly, as well as suppressing dopamine. Human prolactin receptors are insensitive to mouse prolactin7. Prolactin receptor See prolactin receptor Diagnostic use Prolactin levels may be checked as part of a sex hormone workup, as elevated prolactin secretion can suppress the secretion of FSH and GnRH, leading to hypogonadism, and sometimes causing erectile dysfunction in men. Prolactin levels may be of some use in distinguishing epileptic seizures from psychogenic non-epileptic seizures. The serum prolactin level usually rises following an epileptic seizure.8 Conditions causing elevated prolactin secretion Hyperprolactinaemia is the term given to having too-high levels of prolactin in the blood. Prolactinoma Excess thyrotropin-releasing hormone TRH, usually in primary hypothyroidism Many anti-psychotic medications Emotional stress Pregnancy and Lactation. Conditions causing decreased prolactin Bulimia Excess dopamine Use of breastfeeding as contraceptive The World Health Organization states that demand breastfeeding is more than 98% effective as a contraceptive in the first six months postpartum. This effect is said to be responsible for the natural spacing of children seen in countries where contraception is not widely available, and is thought to be an evolutionary means of ensuring adequate care is provided to each newborn. The 98% effectiveness applies only if three criteria are met: The mother has had no menstrual periods at all amenorrhea The baby is exclusively breast-fed It is six months or less since birth. If one or more of these conditions are broken, lactational amenorrhea is no longer a reliable form of birth control. This contraceptive method is highly effective as long as the three conditions stated above are fulfilled. Further, the WHO suggests that a woman that is still amenorrheic has a less-than-5% chance of getting pregnant in the first year of her baby's life, as long as she is still breastfeeding on demand. See also weaning breast-feeding baby food male lactation hormones Prolactin receptor Prolactinoma Hyperprolactinaemia PRLH Psychogenic non-epileptic seizures References ^ Kulick R, Chaiseha Y, Kang S, Rozenboim I, El Halawani M 2005. The relative importance of vasoactive intestinal peptide and peptide histidine isoleucine as physiological regulators of prolactin in the domestic turkey. Gen Comp Endocrinol 142 3: 267-73. doi:10.1016/j.ygcen.2004.12.024. PMID 15935152. ^ New Scientist article on prolactin function relating to sex - University of Paisley and the ETH Zürich ^ Gregg C, Shikar V, Larsen P, et al 2007. White matter plasticity and enhanced remyelination in the maternal CNS. J. Neurosci. 27 8: 1812-23. doi:10.1523/JNEUROSCI.4441-06.2007. PMID 17314279. ^ Prolactinoma - Mayo Clinic ^ Craven AJ, Nixon AJ, Ashby MG, et al November 2006. Prolactin delays hair regrowth in mice. J. Endocrinol. 191 2: 415-25. doi:10.1677/joe.1.06685. PMID 17088411. ^ Melmed S, Jameson JL 2005. 333 Disorders of the Anterior Pituitary and Hypothalamus, in Jameson JN, Kasper DL, Harrison TR, Braunwald E, Fauci AS, Hauser SL, Longo DL.: Harrison's principles of internal medicine, 16th ed., New York: McGraw-Hill Medical Publishing Division. ISBN 0-07-140235-7. ^ Utama FE, LeBaron MJ, Neilson LM, et al 2006. Human prolactin receptors are insensitive to mouse prolactin: implications for xenotransplant modeling of human breast cancer in mice. J. Endocrinol. 188 3: 589-601. doi:10.1677/joe.1.06560. PMID 16522738. ^ Banerjee S, Paul P, Talib V 2004. Serum prolactin in seizure disorders. Indian Pediatr 41 8: 827-31. PMID 15347871. External links Pathophysiology of Endocrine System - Prolactin at colostate.edu MedlinePlus Encyclopedia Prolactin med/1098 at eMedicine - Hyperprolactinemia med/1914 at eMedicine - Prolactin Deficiency v d e Endocrine system: hormones/endocrine glands Peptide hormones, Steroid hormones Hypothalamic-pituitary Hypothalamus: TRH, CRH , GnRH, GHRH, somatostatin, dopamine - Posterior pituitary: vasopressin, oxytocin - Anterior pituitary: α FSH, LH, TSH, GH, prolactin, POMC ACTH, MSH, endorphins, lipotropin Adrenal axis Adrenal medulla: epinephrine, norepinephrine - Adrenal cortex: aldosterone, cortisol, DHEA Thyroid axis Thyroid: thyroid hormone T3 and T4 - calcitonin - Parathyroid: PTH Gonadal axis Testis: testosterone, AMH, inhibin - Ovary: estradiol, progesterone, inhibin/activin, relaxin pregnancy Other end. glands Pancreas: glucagon, insulin, somatostatin - Pineal gland: melatonin Non-end. glands Placenta: hCG, HPL, estrogen, progesterone - Kidney: renin, EPO, calcitriol, prostaglandin - Heart atrium: ANP - Stomach: gastrin, ghrelin - Duodenum: CCK, GIP, secretin, motilin, VIP - Ileum: enteroglucagon - Adipose tissue: leptin, adiponectin, resistin - Thymus: Thymosin - Thymopoietin - Thymulin - Skeleton: Osteocalcin - Liver/other: Insulin-like growth factor IGF-1, IGF-2 Target-derived NGF, BDNF, NT-3 Retrieved from http://en..org/wiki/Prolactin Categories: Genes on chromosome 6 | Peptide hormones | Anterior pituitary hormones | Breastfeeding Views Article Discussion this page History Personal tools Log in / create account Navigation Main page Contents Featured content Current events Random article Search Go Search Interaction Community portal Recent changes Contact Donate to Help Toolbox What links here Related changes Upload file Special pages Printable version Permanent link Cite this page Languages العربية БългарÑ?ки ÄŒesky Deutsch Þ‹Þ¨ÞˆÞ¬Þ€Þ¨Þ„Þ¦Þ?Þ° Español Esperanto Français Bahasa Indonesia Ã?slenska Italiano עברית Lietuvių МакедонÑ?ки Nederlands 日本語 ‪Norsk bokmÃ¥l‬ Polski Português РуÑ?Ñ?кий Shqip SlovenÄ?ina Suomi Svenska Türkçe ä¸æ–‡ This page was last modified on 6 September 2008, at 01:42
39 Reasons to Drink Acai Juice Every Day
What is MonaVie - Watch the 8-minute video
Discovering MonaVie Video
The Power of You Video
Effects of MonaVie Active on Antioxidant Capacity in Humans
Log into your Wholesale MonaVie Account
So many of us do not eat a balanced diet, get enough sleep, have too much stress, or are impacted with toxins and pollutants. Drinking 2 ounces of MonaVie twice a day will help your body detoxify as well as build your immune system. Its the smartest thing you can do for yourself, so start today. Buying MonaVie through our company guarantees you support 7 days a week and, if you would like to share MonaVie with your family and friends we will guide you from start to finish.
1. Click on Enroll Now (30 - 55% off retail price)
2. Pay $39 for your Wholesale ID number.
3. NO minimum order required.
4. MonaVie is delivered to your door in 3 to 5 days.