Luteinizing hormone
Chr. 6 q14-q21 | |||||||
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Luteinizing hormone (LH, also known as luteinising hormone,
Etymology
The term luteinizing comes from the Latin "luteus," meaning "yellow." This is in reference to the corpus luteum, which is a mass of cells that forms in an ovary after an ovum (egg) has been discharged but remains unfertilized. The corpus luteum is so named because it often has a distinctive yellow color. The process of forming the corpus luteum is known as "luteinization," and thus the hormone that triggers this process is termed the "luteinizing" hormone.
Structure
LH is a heterodimeric glycoprotein. Each monomeric unit is a glycoprotein molecule; one alpha and one beta subunit make the full, functional protein.
Its structure is similar to that of the other
- The amino acidsin almost all other vertebrate species (glycoprotein hormones do not exist in invertebrates).
- The beta subunits vary. LH has a beta subunit of 120 amino acids (LHB) that confers its specific biologic action and is responsible for the specificity of the interaction with the LH receptor. This beta subunit contains an amino acid sequence that exhibits large homologies with that of the beta subunit of hCGand both stimulate the same receptor. However, the hCG beta subunit contains an additional 24 amino acids, and the two hormones differ in the composition of their sugar moieties.
The different composition of these oligosaccharides affects bioactivity and speed of degradation. The biologic half-life of LH is 20 minutes, shorter than that of FSH (3–4 hours) and hCG (24 hours).[citation needed] The biological half-life of LH is 23 hours subcutaneous[7] or terminal half life of 10-12 hours.[8]
Genes
The gene for the alpha subunit is located on chromosome 6q12.21.
The luteinizing hormone beta subunit gene is localized in the LHB/CGB gene cluster on
Function
In both males and females, LH works upon endocrine cells in the gonads to produce androgens.
Effects in females
LH supports
Gonadal steroids (
Effects in males
LH acts upon the
LH is released from the pituitary gland, and is controlled by pulses of
Changes in LH and testosterone blood levels and pulse secretions are induced by changes in sexual arousal in human males.[21]
Effects in the brain
Luteinizing hormone receptors are located in areas of the brain associated with
Recent research has observed an inverse relationship between circulating LH and CNS LH levels.[24] After ovariectomy (a procedure used to mimic menopause) in female mice, circulating LH levels surge while CNS levels of LH fall.[25] Treatments that lower circulating LH restore LH levels in the CNS.[25]
Normal levels
LH levels are normally low during
During reproductive years, typical levels are between 1 and 20 IU/L. Physiologic high LH levels are seen during the LH surge (v.s.) and typically last 48 hours.
In males over 18 years of age, reference ranges have been estimated to be 1.8–8.6 IU/L.[27]
LH is measured in
Predicting ovulation
The detection of a surge in release of luteinizing hormone indicates impending
The recommended testing frequency differs between manufacturers. For example, the Clearblue test is taken daily, and an increased frequency does not decrease the risk of missing an LH surge.[33] On the other hand, the Chinese company Nantong Egens Biotechnology recommends using their test twice per day.[34] If testing once per day, no significant difference has been found between testing LH in the morning versus in the evening, in relation to conception rates,[35] and recommendations of what time in the day to take the test varies between manufacturers and healthcare workers.[36] Tests may be read manually using a color-change paper strip, or digitally with the assistance of reading electronics.
Tests for luteinizing hormone may be combined with testing for
The sensitivity of LH tests are measured in
As sperm can stay viable in the woman for several days, LH tests are not recommended for
Disease states
Excess
In children with precocious puberty of pituitary or central origin, LH and FSH levels may be in the reproductive range instead of the low levels typical for their age.
During the reproductive years, relatively elevated LH is frequently seen in patients with polycystic ovary syndrome; however, it would be unusual for them to have LH levels outside of the normal reproductive range.
Persistently high LH levels are indicative of situations where the normal restricting feedback from the gonad is absent, leading to a pituitary production of both LH and FSH. While this is typical in menopause, it is abnormal in the reproductive years. There it may be a sign of:
- Premature menopause
- Gonadal dysgenesis, Turner syndrome, Klinefelter syndrome
- Castration
- Swyer syndrome
- Polycystic ovary syndrome
- Certain forms of congenital adrenal hyperplasia
- Testicular failure
- Pregnancy – BetaHCG can mimic LH so tests may show elevated LH
Note: A medical drug for inhibiting luteinizing hormone secretion is butinazocine.[37]
Deficiency
Diminished secretion of LH can result in failure of gonadal function (hypogonadism). This condition is typically manifest in males as failure in production of normal numbers of sperm. In females, amenorrhea is commonly observed. Conditions with very low LH secretions include:
- Pasqualini syndrome[38][39]
- Kallmann syndrome
- Hypothalamic suppression
- Hypopituitarism
- Eating disorder
- Female athlete triad
- Hyperprolactinemia
- Hypogonadism
- Gonadal suppression therapy
- GnRH antagonist
- GnRH agonist(inducing an initial stimulation (flare up) followed by permanent blockage of the GnRH pituitary receptor)
As a medication
LH is available mixed with FSH in the form of
Often, HCG medication is used as an LH substitute because it activates the same receptor. Medically used hCG is derived from urine of pregnant women, is less costly, and has a longer half-life than LH.
Role in phosphorylation
References
- ^ GCSE Science Revision Biology "The Menstrual Cycle", retrieved 2022-03-23
- PMID 1498420.
- PMID 29102564.
- ^ a b Nosek TM. "Section 5/5ch9/s5ch9_5". Essentials of Human Physiology. Archived from the original on 2016-03-24.
- PMID 1122882.
- PMID 24001578.
- PMID 25280580.
- PMID 9496327.
- ^ Bowen R (13 May 2004). "Gonadotropins: Luteinizing and Follicle Stimulating Hormones". Colorado State University. Retrieved 12 March 2012.
- PMID 22028409.
- PMID 22654832.
- ISBN 978-0-12-396465-6.
- ^ PMID 30969514.
- PMID 29566165.
- PMID 16293774.
- S2CID 13816368.
- PMID 30619093.
- ISSN 0006-3363.
- PMID 24478760.
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- S2CID 23595343.
- PMID 26172857.
- ISSN 2813-3919.
- PMID 30319538.
- ^ PMID 26172857.
- ISSN 2002-4436.
- ^ "Test ID: LH, Luteinizing Hormone (LH), Serum". Mayo Medical Laboratories. Archived from the original on 2016-09-25. Retrieved 1 December 2012.
- ^ WHO Expert Committee on Biological Standardization (2003). "Proposed International Standard for Luteinizing Hormone" (PDF). Geneva: World Health Organization.
- ^ "WHO International Standard, Luteinizing Hormone, Human, Recombinant" (PDF). National Institute for Biological Standards and Control.
- PMID 10402400.
- PMID 11476792.
- ^ "Ovulation Predictor Kit Frequently Asked Questions". Fertility Plus. Archived from the original on March 12, 2012. Retrieved 12 March 2012.[unreliable medical source?]
- ^ "Clear Blue Ovulation Test Instructions". Ovulation Guide. Retrieved 2018-01-19.
- ^ "Advanced Ovulation Test" (PDF). Homehealth-UK. Retrieved 2018-01-19. Version 1.1 02/11/15
- PMID 8059611.
- ^ Meniru GI (2001). Cambridge Guide to Infertility Management and Assisted Reproduction. Cambridge University Press. p. 67.
- ^ US 4406904, Welle HB, Marko M, "Method of inhibiting luteinizing hormone secretion with 6,7-benzomorphan derivatives", issued 27 September 1983, assigned to ACF Chemiefarma NV.
- PMID 1727547.
- PMID 15602022.
- ^ "Luveris information". Archived from the original on June 18, 2006.[unreliable medical source?]
- PMID 32077149.
External links
- Luteinizing+Hormone at the U.S. National Library of Medicine Medical Subject Headings (MeSH)