LH is one of the gonadotropic hormones, in medical terms referred to as lutropin or luteinizing hormone. The test assessing the concentration of this compound in the blood serum is a component of the infertility diagnostic process and is performed both in the population of women and men.
Luteinizing hormone( LH, lutropin ) is a hormone whose concentration in the body is not constant, it changes not only with age, but also during the menstrual cycle. LH secretion peaks at the time of ovulation, therefore the determination of this hormone can be an excellent tool for monitoring ovulation. The importance of LH boils down not only to infertility, but also to a wider diagnosis of diseases such as hypopituitarism, pituitary adenoma or hypogonadism.
Luteinizing hormone (LH, lutropin) - what is it?
LH secretion depends on the stimulation of gonadoliberin (GnRH), the parent hormone produced in the hypothalamus. The luteinizing hormone consists of two subunits and a glycoprotein part.
The highest concentration of LH occurs during ovulation in women and is involved in the formation of the corpus luteum, and also maintains its secretory function. In men, LH stimulates testosterone synthesis in the testes.
Indications for the LH concentration test
Testing the concentration of luteinizing hormone, most often in the case of suspected diseases such as:
- male and female infertility
- menstrual disorders of unknown etiology, suspected of endocrine-related diseases in the form of diseases of the thyroid gland, adrenal glands or ovarian tumors
- diseases of the pituitary gland, e.g. adenomas
- diseases of the gonads of the testicles and ovaries
- setting an ovulation date
- confirmation of menopausal age
- diagnosis of delayed or premature puberty
What is the correct LH level?
LH levels are not constant, not only with the menstrual cycle but also with age. The highest concentration is observed on the day of ovulation, then the concentration drops sharply.
Sustained high levels may be synonymous with menopause and are due to the decline in ovarian function.
The correct LH level is thereforedifferent, at different stages of life or cycle:
- follicular phase 1.4 - 9.6 mlU / ml;
- ovulation 2.3 - 21 mlU / ml;
- postmenopausal 42 - 188 mlU / ml.
Male LH levels are in the range of 1.5 - 9.2 mLU / mL.
What can affect LH levels?
In men, testosterone plays an important role in the concentration of the LH hormone, and their mutual correlation is based on the principle of negative feedback. The decrease in testosterone is reflected in the increasing concentration of LH. The same mechanism, but involving estradiol, occurs in women.
Some drugs can also interfere with hormone synthesis. An example is medications used in seizures.
High levels may be associated with neoplastic growths in the pituitary gland in the form of adenomas. In turn, a low LH level is an expression of pituitary or hypothalamic insufficiency.
- Female hormones: estrogens, progesterone, androgens, prolactin, thyroid hormones
- Endocrine system - structure and functions