Effects of sex steroid hormones on the neuroendocrine system

Estrogen and progesterone are the most important ovarian steroid hormones regulating female fertility. They have a profound effect on the central nervous system. Target functions of sex steroids in the brain are: pituitary and hypothalamic hormone release, thermoregulatory and cardiocirculatory activities and behavior and mood changes. Furthermore, several studies have shown a correlation between brain neurotransmitters, neuropeptides and sex steroid hormones: they influence synthesis and release of norepinephrine, dopamine, serotonin, gonadotropin releasing hormone, β-endorphin, corticotropin releasing factor and prolactin. Thus, oral hormone contraceptives inhibit the ovulatory process by blocking the activity of the hypothalamus-pituitary—gonadal axis. This inhibitory effect seems to be due to the action of both estrogens and progestins.