Androgens refer to the male sex hormones. Among them are: In men, these hormones are produced in the testicles (Leydig cells) and in the adrenal cortex. In women, they are produced in the ovary and also in the adrenal cortex.
In the blood, the transport of androgens takes place either bound to the protein albumin or to the sex hormone-binding globulin (SHBG). As with all steroid hormones, the hormone receptor is located inside the cells (intracellularly). – Testosterone
- Dihydrotestosterone
- Androstenedione
- Dehydroepiandrosterone
Formation of androgens: Like all steroid hormones, androgens are formed from cholesterol.
Pregnenolone and progesterone are intermediates in the synthesis of these hormones. In the adrenal cortex, androstendione and dehydroepiandrosterone are produced as representatives of the androgens, whereby the former is formed from the latter by enzymatic conversion. The hormone androstendione can also be converted into oestrogen or testosterone.
Regulation of androgens: Like the other hormones of the adrenal cortex, androgens are controlled by the hypothalamus via CRH and by the pituitary gland via ACTH. The release of these androgens is subject to a hypothalamic-pituitary control loop: GnRH (gonadotropin releasing hormone) of the hypothalamus, LH (luteinizing hormone) and FSH (follicle stimulating hormone) of the pituitary gland. The GnRH is released pulsatile – every 60 to 90 minutes.
The LH and GnRH release of testosterone and oestradiol is suppressed in the sense of negative feedback. LH acts on the Leydig cells of the testes by increasing testosterone synthesis. FSH acts on other cells of the testis, the Sertoli cells, which produce the substance inhibin and form the androgen binding protein.
The androgen binding protein enables the hormone testosterone to influence sperm maturation. FSH also causes the formation of LH receptors on the Leydig cells. FSH also has a negative feedback loop: FSH release is inhibited by the hormones testosterone, dihydrotestosterone, estradiol and inhibin.
However, it is increased by Activin. Activin is a hormone structurally related to inhibin, the synthesis of which also takes place in the testes. The androgens as hormones of the adrenal cortex accelerate the breakdown of body white and act as sex hormones through their conversion to testosterone or oestrogen, respectively, which cause sexual maturation.