One of the representatives of androgens is the active hormone dihydrotestosterone (DHT). This substance is formed from free testosterone and androstenedione in peripheral tissues under the action of enzyme systems. DHT is the strongest of all natural male sex hormones.
In men, this androgen:
- contributes to the development of the prostate gland and genitals;
- determines secondary sexual characteristics ;
- affects physical development during puberty;
- regulates libido;
- supports potency;
- is the cause of baldness .
Fig. 1 - Increased levels of dihydrotestosterone in men is one of the causes of early baldness.
Norm level dihydrotestosterone
In laboratories, the concentration of DHT is expressed in the following units: pg / ml; ng / 100 ml; nmol / l. The normal level of the hormone is very different in different periods of life. The maximum value of the level of DHT reaches after 15-16 years.
Table 1 - Normal values of dihydrotestosterone in men.
|Age||The minimum value of the norm, pg / ml||The maximum value of the norm, pg / ml|
|1 week of life||120||850|
|2-7 weeks of life||-||24|
|8-10 weeks of life||120||850|
|children up to 10 years||-||24|
|10-11 years old||-||thirty|
|11-12 years old||thirty||170|
|12-13 years old||80||330|
|13-15 years old||220||650|
|over 15 years old||250||990|
The level of hormone is influenced by the intake of androgens and some other drugs. To make the results more accurate, it is advisable to take the analysis in the morning and on an empty stomach. From the last meal should pass from 8 to 14 hours. The day before the study, you must give up alcohol and avoid overeating (more on how to pass the test for testosterone ).
A change in the concentration of DHT may indicate a serious malfunction of the reproductive system and other disorders. Men with pathological results of the hubbone analysis should be examined by an endocrinologist, andrologist and urologist.
Increased levels of DHT
The reason for the excessive concentration of this active androgen may be excessive secretion of sex hormones in men. Also, the use of medications with steroids and congenital anomalies of enzyme systems leads to an increase in the level of DHT.
Excess DHT is observed in patients with:
- testicular feminization (Morris syndrome);
- malignant neoplasms of the adrenal glands or testicles;
- adrenal or testicular adenomas ;
- idiopathic hirsutism (increased expression of 5-alpha reductase in the skin);
The consequence of increased hormone concentrations in childhood is premature sexual development in an isosexual type. In boys in such cases there is an acceleration of growth, an increase in the percentage of muscle tissue, the appearance of hair on the face and body, and a mutation of the voice. It also reveals an increase in the volume of the testes and prostate, the length of the penis and pigmentation of the skin of the scrotum. True complete sexual development is accompanied by the activation of spermatogenesis.
In adult males, an excessive concentration of DHT causes:
- benign prostatic hyperplasia;
- prostate cancer.
Fig. 2 - Dihydrotestosterone is responsible for the manifestation of secondary sexual characteristics, such as hair on the face and body.
If a high level of androgens is determined in patients with Morrison syndrome, then these features are not observed. Patients with this genetic defect have inborn tissue insensitivity to testosterone and its derivatives. In the full form of the syndrome, a female phenotype is observed (developed mammary glands, vagina) with the male chromosome set (46 XY).
If the cause of increased secretion of DHT is a tumor of the adrenal gland or testicle, then patients usually show increased symptoms over time. If the tumor is malignant, then the negative dynamics is especially noticeable. In addition, other signs of the disease can be observed during tumor processes (compression of surrounding tissues, hemorrhages, cancer intoxication, lymphadenopathy, etc.)
Low values of dihydrotestosterone in men are due to congenital anomalies of steroidogenesis. If the body does not have the enzyme 5-alpha reductase, then DHT is not formed from testosterone. In men with such a genetic feature, at the time of birth, pathologies in the structure of the genital organs are determined.
The role of DHT in the prenatal period is the formation of the external genitalia. If the fetus has a chromosomal set of 46 XY, but the synthesis of dihydrotestosterone is impaired, then the gonads will be male (testicles), and the vulva will be of an intermediate type.
Other causes of lowering DHT:
- primary hypogonadism ;
- secondary (central) hypogonadism;
- age androgen deficiency ;
- the use of drugs inhibitors for 5-alpha reductase .
In adolescents, deficiency of DHT is manifested in delayed puberty or in slowing puberty. Most often there is no growth of hair on the face and body of the male type, there is no increase in the size of the penis, testicles, prostate.
In adult males, an active androgen deficiency is manifested by feminization:
- decreases the percentage of muscle mass;
- hair growth on the face and body slows down;
- decreased libido;
- infertility develops;
- potency deteriorates.
Treatment of imbalance DHT
Correction of the level of DHT is carried out after a full diagnosis and under the control of laboratory parameters (androgens, etc.). The treatment is most often selected by a urologist or an endocrinologist.
Operational treatment helps to reduce DHT in case of tumor of the testicles or adrenal glands. Adenoma (carcinoma) is surgically removed. If necessary, the intervention is supplemented with chemotherapy or radiation therapy.
When excessive activity of 5-alpha-reductase for the treatment can be selected drugs inhibitors of this enzyme. From the medicines of this series in clinical practice two main ones are used: finasteride and dutasteride. The first one was synthesized over 30 years ago. It has a high affinity for type 2 alpha reductase. In medium doses, the drug reduces the level of DHT by 70-90%. Dutasteride combines with the enzyme and 1, and 2 types. Due to this, its effectiveness is slightly higher than finasteride (reduces DHT by 95-98%).
Also, the level and effect of male hormones are influenced by anti-androgen drugs. These drugs inhibit the synthesis of DHT or prevent its binding to receptors of target cells.
Antiandrogens are divided into 2 groups:
- steroids (cyproterone acetate, chlormadinone acetate, megestrol acetate, spironolactone);
- non-steroid (flutamide, anandron, casodex).
In case of premature sexual maturation, drugs are used to suppress the secretion of the pituitary and hypothalamic hormones. For example, a boy may be assigned synthetic analogues of prolonged-acting lutropin releasing hormone.
We increase dihydrotestosterone
In case of primary and secondary hypogonadism, hormone replacement therapy can increase dihydrotestosterone (usually testosterone preparations are used).
In the case of functional impairment, lifestyle modification may be recommended to men. To increase the concentration of androgens in the blood in such situations helps normalization of sleep and wakefulness, moderate exercise, good nutrition, the rejection of bad habits.
If drugs caused by 5-alpha reductase inhibitors are the cause of DHT deficiency, then the question of their cancellation is considered.
Endocrinologist Tsvetkova I.G.