TY - CHAP M1 - Book, Section TI - Disorders of the Testes and Male Reproductive System A1 - Bhasin, Shalender A1 - Jameson, J. Larry A2 - Jameson, J. Larry Y1 - 2017 N1 - T2 - Harrison's Endocrinology, 4e AB - The male reproductive system regulates sex differentiation, virilization, and the hormonal changes that accompany puberty, ultimately leading to spermatogenesis and fertility. Under the control of the pituitary hormones—luteinizing hormone (LH) and follicle-stimulating hormone (FSH)—the Leydig cells of the testes produce testosterone and germ cells are nurtured by Sertoli cells to divide, differentiate, and mature into sperm. During embryonic development, testosterone and dihydrotestosterone (DHT) induce the wolffian duct and virilization of the external genitalia. During puberty, testosterone promotes somatic growth and the development of secondary sex characteristics. In the adult, testosterone is necessary for spermatogenesis, stimulation of libido and normal sexual function, and maintenance of muscle and bone mass. This chapter focuses on the physiology of the testes and disorders associated with decreased androgen production, which may be caused by gonadotropin deficiency or by primary testis dysfunction. A variety of testosterone formulations now allow more physiologic androgen replacement. Infertility occurs in ~5% of men and is increasingly amenable to treatment by hormone replacement or by using sperm transfer techniques. For further discussion of sexual dysfunction, disorders of the prostate, and testicular cancer, see Chaps. 19, and 12, respectively. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - accessbiomedicalscience.mhmedical.com/content.aspx?aid=1141274911 ER -