Endocrinopathies

Spermatogenesis depends on an intricate interplay of hormonal factors both centrally and in the testis. Centrally, the hypothalamus releases gonadotropin-releasing hormone (GnRH), which acts on the anterior pituitary to cause secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). At the level of the testis, FSH acts on Sertoli cells to induce the maturation process in spermatogonia. LH exerts its effect on Leydig cells, stimulating production of testosterone. Effective spermatogenesis requires local testosterone concentrations to be much higher than serum concentrations. This intratesticular testosterone then acts indirectly to stimulate germ cell maturation through actions on Sertoli cells. Although endocrinopathies only account for a small minority of cases of male infertility, about 1–2%, the treatment of these conditions offers patients a strategy of directed therapy. Broad classification of endocrinopathies involves two main categories: hormonal deficiency and hormonal excess, with specific hormonal abnormalities falling under each of the above categorizations.