Luteinizing hormone (LH or also called lutropin) is a hormone from the pituitary gland (hypophysis) that, with the cooperation of follicle-stimulating hormone (FSH), controls follicle maturation (egg maturation) and ovulation (ovulation) in women. It is also involved in estrogen and progesterone synthesis. In men, LH (interstitial cell stimulating hormone = ICSH) controls the production of androgens in the testes. LH itself is controlled by gonadotropin-releasing hormone (GRH), which is produced in the hypothalamus. LH shows a cycle-dependent rhythmicity with a strong peak in the middle of the cycle. It is released in a pulsatile manner, and basal LH levels are highly variable throughout the day from puberty and in women until menopause.
The procedure
Material needed
- Blood serum
- Best date for blood collection in women: 2-5 days after the onset of menstruation; to detect the time of ovulation (ovulation) blood collection in the middle of the cycle.
- Note: determination in women from pool serum may be beneficial due to pulsatile release of LH
Preparation of the patient
- Not necessary
Disruptive factors
- None known
Normal values children
| Age | Normal values in U/l |
| 2nd-12th day of life (LT). | < 0,1-0,5 |
| 2-11 years of age (LY) | < 0,1-0,4 |
| 12TH-13TH LY | < 0,1-5,4 |
| 14-18 LY | 0,5-12,9 |
Normal values women
| Cycle | Normal values in U/l |
| Follicular phase | 2-6 |
| Ovulation | 6-20 |
| Luteal phase | 3-8 |
| Menopause | > 30 |
Normal values men
| Cycle | Normal values in U/l |
| Prepubertal | 0,2-0,8 |
| Postpubescent | 0,8-8,3 |
Indications
- Sterility diagnostics
- Suspicion of ovarian insufficiency – functional weakness of the ovaries such as in disorders during puberty or menopause (menopause).
- Suspected testicular insufficiency (hypogonadism; DD hypo- or hypergonadotropic) – functional weakness of the testes as a hormone-producing organ.
- Disruption of spermatogenesis (spermatogenesis).
- Disorders of pubertal development (of the male) – pubertas tarda; pubertas praecox.
Interpretation
Interpretation of elevated values in women
- Gonadal dysgeneses (e.g., Turner syndrome) – maldevelopment of the gonads.
- Klimakterium praecox (premature menopause) – menopause that occurs too early; between the 25th and 40th year of life.
- Ovulation (ovulation)
- Drug administration of human chorionic gonadotropin (HCG) – pregnancy hormone.
- Polycystic ovary syndrome (PCO syndrome) – disease that leads to hormonal changes due to the appearance of multiple cysts on the ovaries (ovaries).
- Postmenopausal – condition after menopause.
- Cytostatic therapy – drugs used primarily for cancer.
Interpretation of elevated values in men
- Androgen resistance (testosterone ↑)
- Primary testicular insufficiency
- Testicular atrophy – testicular shrinkage; results in limited to completely abolished sperm production.
- Inguinal testis
- Leydig cell dysfunction
- Hypergonadotropic hypogonadism (gonadal dysgenesis) – maldevelopment of the gonads.
Interpretation of lowered values in women
- Secondary ovarian insufficiency
- Anorexia nervosa (anorexia nervosa)
- Olfactogenital syndrome (Kallmann) – genetic disorder based on a deficiency of sex hormone.
- Hyperprolactinemia – excessive level of prolactin in the blood.
- McCune-Albright syndrome – combination of fibroplasia, pigmentary abnormalities and hormone dysfunction.
- Sex steroid therapy (hormonal contraceptives; hormone replacement therapy) – drug therapy with ovulation inhibitors (“the pill”) or use of sex steroids.
Interpretation of lowered values in men
- Hypogonadotropic hypogonadism (testosterone ↓) – gonadal hypofunction due to hypothalamic or pituitary disorders.
- Secondary testicular insufficiency (testosterone ↓) – disorder of hormone production by the testis.
- Testosterone therapy (testosterone is normal to increased).
Other notes
- When interpreting the measured values, the cycle phase must always be taken into account, i.e. it is always necessary to specify the cycle day on the day of blood collection or the first day of the last menstrual period.
- LH should always be determined in combination with FSH
