Formation of estrogen: Estrogens as components of the steroid hormones are formed from the hormone androstendione. These hormones are formed in the ovaries (ovaries), placenta, adrenal cortex and testicles (testis). The hormone producing cells in the ovaries are the granulosa and theca cells, in the testis the Leydig intermediate cells.
The following estrogen representatives exist: After their release into the blood, the estrogens are bound to the transport protein SHBG (sex hormone binding globulin). The receptor of these hormones is located within the cells, i.e. intracellularly.
- Estradiol
- Östron
- Östriol
Regulation of estrogen: Estrogens are part of the hypothalamic-pituitary axis.
The hypothalamic hormone GnRH (gonadotropin releasing hormone) is released pulsatile, which means that it is released as a “pulse” for a duration of about one minute every 60 to 90 minutes. In the pituitary gland, the hormones FSH (follicle stimulating hormone) and LH (luteinizing hormone) are also secreted pulsatile. The release of LH and FSH is modulated by estrogens, progesterone and inhibin.
Inhibin is produced in the granulosa cells of the ovaries and in the Sertoli cells of the testes as a peptide hormone. The estrogens as part of the reproductive hormones influence the development of the female reproductive organs (breast, vagina, fat distribution, pubic hair). Moreover, these hormones participate in the course of the female menstrual cycle.
This is done by the hormones promoting the build-up of the uterine lining and indirectly acidifying the vaginal milieu via cell surface changes, which in turn reduces the risk of infection, as fewer bacteria settle under these conditions. In the vagina, estrogens also change the composition of the cervical mucus so that penetrating sperm can penetrate it more easily and survive better. The hormones also influence the speed at which the eggs migrate through the fallopian tubes, making it easier for sperm to penetrate the egg.
In this way, the hormones promote fertilization as a whole. Effects of the hormones outside of reproduction include influences on blood clotting, which is increased, and on water and salt excretion, which is decreased. At the bones, estrogens prevent growth and force the closure of the growth joints (epiphyseal joint closure).
The distribution of lipoproteins, which are used to transport cholesterol and other fats in the blood, is also altered in such a way that LDL (low densitiy lipoprotein) is lowered, while VLDL (very low densitiy lipoprotein) and HDL (high densitiy lipoprotein) are increased, which in all probability results in a lower risk of arteriosclerosis, among other things. Furthermore, estrogens also change the skin, which becomes softer and thinner. The number of sebaceous glands is reduced and the amount of subcutaneous fatty tissue is increased by the hormone. The last effect of these hormones is the one on behaviour and psyche.
