Reproduktivni hormoni i manipulacija hormonima u terapiji infertiliteta

Sex steroids and the activity of the hypothalamo-pituitary-gonadal axis are the key components indicate the proper function of the reproductive axis. Testosterone represents main male sex steroid whose synthesis depends upon the number of the functional Lydig cells and stimulation of the gonadal axis. Besides specific hydroxilase and dehyrogenases, steroid regulatory protein represents important regulator of testosteron synthesis, and takes part in the neuro-steroid production. For the initiation of the steroid synthesis, effect of gonadotropin-releasing hormone on the pulse secretion of gonadotropins is important, and that could be modulated by different neuro-regulatory molecules. Spermatogenesis starts in puberty under the influence of folliculostimulated hormone (FSH) and is in direct relation to inhibin B that is considered a clinical marker of spermatogenesis. After birth and cesation of the placental steroids influence, ovary is activated under the influence of increased FSH. This influence is expressed through increased inhibin B and estradiol concentrations. It seems that metabolic and neuroregulatory signals, adipocyte derived factor leptin and kisspeptin, plays a role in the activation of the reproductive axis in prepubertal period. During folliculogenesis, estrogen synthesis from cholesterol requests tight functional connection of the theca and granulosa cells, and that is traditionally named 'two-cell model of steroidogenesis'. Most of the reproductive axis actions is mediated by nuclear receptors that changes their expression during menstrual cycle. Taking into consideration clear role of steroid hormones in the preservation of fertility in women, it is of importance use of the reproductive hormones and monitoring of their application in modern assisted reproductive techniques protocols.