Androgens

introduction

Androgens refer to the male sex hormones. They include:

• testosterone
• Dihydrotestosterone
• Androstenedione
• Dehydroepiandrosterone

The places where these hormones are formed are in the male testes (Leydig cells) and in the adrenal cortex, in women in the ovary and also in the adrenal cortex. In the blood, the androgens are 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 (intracellular).

education

Formation of androgens:

Like all Steroid hormones arise Androgens out cholesterol. Intermediate products in the synthesis of these hormones are pregnenolone as well progesterone are represented in the adrenal cortex as representatives of the Androgens Androstenedione and Dehydroepiandrosterone are produced, the former being formed from the latter by means of enzymatic conversion. The hormone androstenedione can also be found in estrogen or testosterone be transformed.

regulation

Regulation of androgens:

Like the rest of them Hormones androgens are controlled by the adrenal cortex via CRH Hypothalamus and over ACTH those of the pituitary gland.

The release of these androgens is subject to a hypothalamus-pituitary control circuit: GnRH (Gonadotropin R.eleasing Hormone) of the hypothalamus, LH (L.uteinizing Hormon) and FSH (F.olliclestimulating Hormon) of the pituitary gland.
The GnRH is released in a pulsatile manner - every 60 to 90 minutes. The release of LH and GnRH is prevented testosterone as well as estradiol in the sense of a negative feedback. LH acts on the Leydig cells of the testicle by increasing testosterone synthesis. FSH acts on other cells of the testicle, the Sertoli cells, which in the course of this produce the substance inhibin and form the androgen binding protein.
The androgen binding protein enables the hormone testosterone to influence sperm maturation. In addition, FSH causes the development of LH receptors on the Leydig cells.

There is also a negative feedback with FSH: The release of FSH 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.

function

The androgens as Adrenal hormones accelerate the breakdown of body white and act by converting it testosterone respectively estrogen as sex hormones that cause sexual maturation.