[Physiology and exploration of the gonadotropic axis].

The physiology of the hypothalamus-pituitary-gonadal axis includes endocrine interactions between the hypothalamopituitary system and the gonads, as well as paracrine interactions within the various endocrine glands of the reproductive system (pituitary, ovary, testis). The pulsatile secretion of GnRH by the hypothalamus stimulates the pulsatile secretion of gonadotropins (LH and FSH) by the pituitary. LH and FSH regulate the hormonal production of the gonads as well as gametogenesis. The steroid (oestradiol, progesterone, testosterone) and peptide (inhibins) hormones produced by the gonads regulate in turn hypothalamopituitary secretions. The exploration of the hypothalamo-pituitary-gonadal axis relies mainly on the analysis of few, carefully scheduled, basal state hormonal evaluations. A confrontation of these hormonal assessments with physical examination is crucial.