Annales d'endocrinologie
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Annales d'endocrinologie · May 2014
ReviewCongenital hypogonadotropic hypogonadism and Kallmann syndrome as models for studying hormonal regulation of human testicular endocrine functions.
Men with Kallmann syndrome (KS) and those with congenital isolated hypogonadotropic hypogonadism with normal olfaction share a chronic, usually profound deficit, in FSH and LH, the two pituitary gonadotropins. Many studies indicate that this gonadotropin deficiency is already present during fetal life, thus explaining the micropenis, cryptorchidism and marked testicular hypotrophy already present at birth. In addition, neonatal activation of gonadotropin secretion is compromised in boys with severe CHH/Kallmann, preventing the first phase of postnatal testicular activation. ⋯ The effects of these pharmacological probes can be assessed by measuring the changes they provoke in circulating testicular hormone concentrations. This review discusses the impact of chronic gonadotropin deficiency on the endocrine functions of the interstitial compartment, which contains testosterone-, estradiol- and INSL3-secreting Leydig's cells. It also examines the regulation of inhibin B and anti-Mullerian hormone (AMH) secretion in the seminiferous tubules, and the insights provided by studies of human testicular stimulation with recombinant gonadotropins, used either individually or in combination.