The gonadotropic cells of the pituitary gland produce a hormone known as luteinizing hormone (LH), also commonly known as lutropin.
GnRH (Gonadotropin releasing hormone) from the hypothalamus has a role in controlling the synthesis of luteinizing hormone.
Ovulation and formation of corpus luteum, both essential for the development of the fetus, are brought on by an abrupt increase in luteinizing hormone, known as the luteinizing hormone surge.
The formation of ovulation in females and the corpus luteum are Luteinizing hormone is known as ICSH (interstitial cell-stimulating hormone) in males. It increases the creation of testosterone by Leydig cells.
Combined with follicle-stimulating hormones, it has a beneficial effect. In this article, we will be looking at all about luteinizing hormones.
What Is Luteinizing Hormone?
Luteinizing hormones, also known as gonadotropic hormones, are created and released by a collection of pituitary gland cells.
It is one of the primary hormones which regulates the reproductive system by regulating the function of both female and male reproductive organs, specifically the testes in males and ovaries in females.
Gonadotropin-releasing hormone is released from the hypothalamus and binds to receptors in the anterior pituitary gland, which stimulates both the synthesis and release of luteinizing hormone in the bloodstream.
The ovaries are the next stop on their journey. Luteinizing hormone is kept at a constant level in blood cells by the body.
However, a rise in estrogen causes the luteinizing hormone to increase, which causes ovulation. Ovulation is the release of an egg cell from an ovary in females.
Luteinizing hormone stimulates the testes’ secretion and synthesis of androgen hormones among males.
This hormone also regulates the spermatogenesis process and the release of the FSH (follicle stimulating hormone) and androgens.
The Graafian follicles present in females are stimulated for ovulation by the luteinizing hormone.
Luteinizing hormone also maintains the corpus luteum, which is developed from the Graafian follicles’ remnants after ovulation. One of its main functions is to generate progesterone, which is essential in the early stages of pregnancy.
Purpose Of Luteinizing Hormone
When your body requires luteinizing hormone, it is produced in the hypothalamus section of the pituitary gland and is then released into the bloodstream.
Similar to FSH (follicle stimulating hormone), a luteinizing hormone in women handles the maturing eggs and causes the ovaries to produce estrogen.
It also triggers ovulation, which explains the sudden surge in luteinizing hormone levels in the bloodstream right before ovulation.
The luteinizing hormone blood level drops after ovulation. One of the primary causes of difficulty to conceive might be your body not producing enough luteinizing hormone.
Because of this, luteinizing hormone is also utilized in reproductive therapies like in vitro fertilization (IVF).
During in vitro fertilization preparation, both the follicle-stimulating hormone and the luteinizing hormone are administered into a woman’s body to make sure that a majority of eggs mature at once.
How Does Body Calculate The Requirement Of Luteinizing Hormone?
Your gonadotropin-releasing hormone (GnRH) regulates the amount and timing of the required luteinizing hormone release.
The anterior pituitary gland in your brain releases the luteinizing hormone, which stimulates the production of estrogen and testosterone.
If there is enough LH present, the body will reduce the production of gonadotropin-releasing hormone.
A high concentration of LH causes ovulation, which is closely coordinated with different hormones and connected to your monthly cycle.
Under the action of the luteinizing hormone after the ovulation process, the remaining follicle changes back into the corpus luteum. Estrogen and progesterone are created as a result of this process.
Luteinizing hormone is also a crucial component within males among couples seeking to conceive, as it not only promotes the maturation of sperm but also the production of testosterone.
What Is Luteinizing Hormone Cycle?
The level of luteinizing hormone in your bloodstream is lower during menstruation.
However, it progressively starts increasing again as your menstruation comes to an end. This spike assures that your body produces progesterone.
Estrogen stimulates the growth of an ovarian follicle which contains the egg and the endometrium (also known as the uterine lining) during the first 2 weeks of the cycle.
When estrogen levels are at their maximum limit, the pituitary gland gets prompted to release more FSH and luteinizing hormones. This in turn causes ovulation to begin.
The egg gets discharged into the fallopian tube from the ovary’s follicle during ovulation.
Following ovulation, the luteinizing hormone makes sure that an empty follicle is developed into a corpus luteum.
After ovulation the levels of FSH and LH decline again. Progesterone rises significantly during this period.
Progesterone is a hormone that makes sure that the uterine lining receives more blood supply, making it more porous and softer.
Through this mechanism, the uterine lining gets prepared to receive the fertilized egg.
The level of progesterone in the bloodstream decreases if the egg does not get fertilized. The outer layer of the uterine lining gets separated.
It is washed out by the body through menstruation and the uterine lining is again supplied with less blood.
Normal Reading Of Luteinizing Hormone
When measuring hormones, there is no particular value like there is e.g. for blood sugar. Most hormonal concentrations are influenced by your circadian cycle.
This implies that the values could change, for instance, during the rhythm of night and day or seasonal changes.
The female sex hormones necessary for proper reproduction are related to the progression of the female cycle.
The luteinizing hormone could be identified both in the urine and blood as the values in blood coincide with the urine values since the blood gets transported throughout each organ in the body.
The measured results show the amount of luteinizing hormone the pituitary gland was producing at the moment of sampling.
It is crucial to collect a blood sample at the correct time of the cycle depending on what you want to look at while determining the luteinizing hormone level.
The level of the normal ranges and the results might differ significantly from lab to lab.
The luteinizing hormone measurements alone are rarely sufficient for determining ovulation or obtaining a statement in the cycle monitoring.
Because of this, the doctor performing the test should interpret each measured value with great caution.
Therefore, results that deviate from the normal range could only be categorized as too high or too low for the relevant examined purpose.
When Does Luteinizing Hormone Gets Low?
An impairment of the hypothalamus or anterior pituitary gland might be the reason for very low levels of both FSH and LH.
If the anterior pituitary gland gets affected by some process, it might not produce the required amount of luteinizing hormone.
Luteinizing hormone production might also stop if the hypothalamus is completely unable to produce an adequate quantity of GnRH.
Wounds, tumors, or environmental variables like anorexia or severe sports could be examples of potential causes.
When Does Luteinizing Hormone Get High?
One possibility for the cause of a high luteinizing hormone is PCOS (polycystic ovary syndrome).
Ovulation does not necessarily have to occur, even if a laboratory test’s results show that it is about to happen.
Additionally, the luteinized unruptured follicle (LUF) syndrome might result in luteinized hormone elevated levels, as per this study.
In luteinized unruptured follicles, ovulation is indicated by LH and other hormones, but the follicle does not burst.
Luteinizing hormone concentration therefore would be seen as too high for the clinical setting as the egg is not able to enter the fallopian tube.
When high quantities of FSH and LH are seen in blood samples, the ovaries could be the source of the issue as well.
The pituitary gland and hypothalamus detect when the ovaries are not working properly and produce inadequate amounts of progesterone and estrogen.
High quantities of FSH and LH are consequently given to patients to help in the stimulation of the ovaries.
What Is A Luteinizing Hormone Blood Test?
The level of luteinizing hormone in your bloodstream is determined by LH blood test.
The quantity of this hormone in your blood varies during the menstrual cycle and aging process. Pregnancy also makes alterations to it.
A woman might require several tests to monitor the varying levels of hormones if a doctor prescribes a luteinizing hormone test for fertility purposes.
A urine test could also be used to determine the levels of luteinizing hormones.
To determine the luteinizing hormone level if you are a man, your doctor might prescribe a luteinizing hormone test for you as well.
Following a hormone injection to release gonadotropin, your doctor could additionally check the luteinizing hormone level.
If you have an issue with your luteinizing hormone after taking the gonadotropin-releasing hormone, your doctor might find out by measuring it.
What Is The Need For Luteinizing Hormone Test?
The luteinizing hormone test helps in quantifying the level of luteinizing hormone in a patient’s bloodstream.
It is also utilized to find pituitary gland-related issues or sexual abnormalities.
These tests are most often used to diagnose the following in men:
- Reasons for low sperm count.
- Causes of a lack of sexual desire.
- Reasons for infertility.
- Causes of discontinued or erratic menstrual cycles.
- Reasons for infertility.
- To determine whether a woman has entered premenopause or menopause.
- Identify the ovulation time.
Multiple problems related to fertility and development could be detected by luteinizing hormone testing.
The test could reveal more information if your doctor has concerns about a disorder that might impact your brain regions responsible for the production of luteinizing hormone or your ovaries, or your testicles.
A doctor might tell whether a female or a male has reproductive system issues based on the results of the luteinizing hormone test.
Luteinizing hormone tests are also used by doctors in identifying issues with the timing of puberty and the pituitary gland.
Women could use luteinizing hormone urine testing which is performed at home to determine their ovulating period.
Evaluation of this test might help them conceive as a woman’s fertile period is right around the time of ovulation.
Working4Health prefers using primary and verified references. We have strict sourcing guidelines and our primary references include peer-reviewed research, academic, and medical institution studies.
- Daniel Nedresky; Gurdeep Singh. Physiology, Luteinizing Hormone Last Update: September 28, 2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539692/
- Samah H. Suede; Ahmad Malik; Amit Sapra. Histology, Spermatogenesis Last Update: March 9, 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK553142/
- J S Richards Graafian follicle function and luteinization in nonprimates J Soc Gynecol Investig. 2001 Jan-Feb;8(1 Suppl Proceedings):S21-3. doi: 10.1016/s1071-5576(00)00100-3. Available from: https://pubmed.ncbi.nlm.nih.gov/11223365/
- Jennifer Choe; Johanna S. Archer; Anthony L. Shanks. In Vitro Fertilization Last Update: May 1, 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562266/
- Beverly G Reed and Bruce R Carr. The Normal Menstrual Cycle and the Control of Ovulation Last Update: August 5, 2018. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279054/
- Luteinizing Hormone (LH) Levels Test Last updated December 17, 2020 Available from: https://medlineplus.gov/lab-tests/luteinizing-hormone-lh-levels-test/
- Katherine Chang, BS and Lubo Zhang Steroid Hormones and Uterine Vascular Adaptation to Pregnancy Reprod Sci. 2008 May; 15(4): 336–348.
- Don S. Schalch, Albert F. Parlow, Robert C. Boon, et al. Measurement of human luteinizing hormone in plasma by radioimmunoassay J Clin Invest. 1968 Mar; 47(3): 665–678.doi: 10.1172/JCI105762
- Syed Razi H. Kazmi; Ahmet S. Can. Luteinizing Hormone Deficiency Last Update: May 13, 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562219/
- A H Balen Hypersecretion of luteinizing hormone and the polycystic ovary syndrome Hum Reprod. 1993 Nov;8 Suppl 2:123-8. doi: 10.1093/humrep/8.suppl_2.123. Available from: https://pubmed.ncbi.nlm.nih.gov/8276945/
- P R Koninckx, P De Moor, I A Brosens Diagnosis of the luteinized unruptured follicle syndrome by steroid hormone assays on peritoneal fluid Br J Obstet Gynaecol. 1980 Nov;87(11):929-34. doi: 10.1111/j.1471-0528.1980.tb04454.x. Available from: https://pubmed.ncbi.nlm.nih.gov/7437365/
- Luteinizing hormone (LH) blood test Available from: https://medlineplus.gov/ency/article/003708.htm
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Otella has an experience of around eight years of writing about health and nutrition-related topics. She is a full-time mother and a housewife, and the time she has left after doing her mother and household duties is spent writing for Working for Health as a full-time writer. Her life goal is to raise both her boys into a gentleman, and at the same time, she wants to educate people on how to keep themselves fit by tweaking their daily diet.