The anterior pituitary gland produces and releases luteinising hormone, a gonadotrophic hormone; Similar to follicle-stimulating hormone. It’s essential for men’s testes and women’s ovaries to operate effectively.
The luteinising hormone stimulates Leydig cells in the testes to release testosterone, which aids sperm production locally. Testosterone also has effects all throughout the body, causing male characteristics such as increased muscle mass, laryngeal enlargement for a deep voice, and facial and body hair growth.
During the menstrual cycle, the luteinising hormone has two distinct roles in women. Luteinising hormone is required in weeks one and two of the cycle to stimulate the ovarian follicles in order for the female sex hormone, estradiol, to be produced. Ovulation occurs when luteinizing hormone levels increase around day 14 of the cycle, prompting the ovarian follicle to disintegrate and release a mature oocyte (egg) from the ovary. For the rest of the cycle, the ovarian follicle leftovers form a corpus luteum (weeks three to four). If fertilisation occurs, the luteinising hormone causes the corpus luteum to release progesterone, which is required to keep the pregnancy going in the early stages.
Luteinising hormone level test can be employed for the following signs and symptoms:
Health care professionals prescribe this test when the individual is a female who has trouble getting pregnant (infertility) and the healthcare provider needs to find out the cause. Individuals also have this test if they have symptoms of a pituitary disorder, such as benign tumours in the pituitary gland (called a prolactinoma).
- Females also have this test if they are having irregular menstrual periods
- Impotence is when a man has difficulty getting or retaining an erection, or when he has a decreased sex drive.
- Breastmilk production starts in women who are not pregnant or breastfeeding
Infertility can be caused by too much luteinizing hormone. Because the hypothalamic-pituitary-gonadal network regulates luteinising hormone secretion, high levels of luteinising hormone in the blood can signify lower sex steroid synthesis from the testicles or ovaries (for eg, as in premature ovarian failure). Just before age of 40, the ovaries lose their natural function. The ovaries don’t create enough oestrogen or release eggs on a regular basis during early menopause. Infertility is a prevalent problem. However, with therapy, a woman with this illness may be able to conceive.
Polycystic ovarian syndrome is a prevalent illness in women that is characterised by excessive luteinizing hormone levels and decreased fertility. An imbalance between the luteinising hormone and follicle-stimulating hormone can lead to inaccurate testosterone production in this syndrome.
Elevated luteinising hormone levels can also be caused by genetic diseases such as Klinefelter’s syndrome and Turner syndrome. Klinefelter’s syndrome is a male-specific illness caused by an extra X chromosome (so that men have XXY, rather than XY chromosomes). As a result, the testes are immature and do not generate sufficient testosterone to maintain sperm production. Turner syndrome is a female-only syndrome caused by a partial or complete X-chromosome deletion (so that women have XO, rather than XX). Ovarian function is impaired in affected patients, so luteinizing hormone production shoots up to try to stimulate ovarian function.
A threshold of luteinising hormone is essential to support testicular or ovarian function, thus too little luteinising hormone will result in infertility in both men and women.
Kallmann’s syndrome, which is associated with a defect in gonadotrophin-releasing hormone release from the hypothalamus, is an example of a disorder in which low levels of the luteinising hormone are detected in men.
Ovulation does not occur in women who already are deficient in luteinizing hormone, and menstrual cycles may be irregular. Amenorrhoea is one example of a condition that can be caused by the lack of luteinising hormone.
Test results differ depending on age, gender, medical history, technique, and other factors. It’s plausible that the test results don’t reveal a specific condition.
International units per litre are used to express the results. The usual range for a woman changes according to her menstrual cycle’s timing. The following are typical ranges:
- 1.42-15.4 International units per litre in men
- 1.37-9 International units per litre in women during the follicular phase of the menstrual cycle
- A midcycle peak in women: 6.17-17.2 International units per litre
- Luteal phase in women: 1.09-9.2 International units per litre
- Postmenopausal women: 19.3-100.6International units per litre
In females, abnormally high levels of LH during the menstrual cycle’s nonovulatory periods could signify that they are signs of approaching menopause. It could potentially indicate a pituitary problem or polycystic ovary syndrome. Low LH levels may indicate a pituitary disease, anorexia, malnutrition, or a high-stress situation.
Male’s excessively high LH levels combined with low testosterone levels could indicate that their testicles aren’t responding to the signal from LH to produce more testosterone. Low levels of LH could indicate that the pituitary gland isn’t producing enough of the hormone.