title: Adult-onset idiopathic hypogonadotropic hypogonadism--a treatable form of male infertility.
abstract: BACKGROUND
  Men with isolated gonadotropin-releasing hormone (GnRH) deficiency typically present with an absence of pubertal development. We describe an adult-onset form of idiopathic hypogonadotropic hypogonadism that develops after puberty.
  
  
  METHODS
  We studied 10 men (age, 27 to 57 years) with normal sexual maturation, idiopathic infertility, sexual dysfunction, low serum testosterone concentrations, and apulsatile secretion of luteinizing hormone on frequent blood sampling. All the men had otherwise normal anterior pituitary hormone secretion and sellar anatomy. We compared the results of semen analyses and measurements of testicular volume, serum testosterone, inhibin B, and gonadotropins in these men with the results in 24 men with classic GnRH deficiency before and during GnRH-replacement therapy and in 29 normal men of similar age.
  
  
  RESULTS
  Serum gonadotropin concentrations in the men with adult-onset GnRH deficiency were similar before and during pulsatile GnRH administration to those in the men with classic GnRH deficiency. However, as compared with men with classic GnRH deficiency, men with adult-onset hypogonadotropic hypogonadism had larger mean (+/-SD) testicular volumes (18+/-5 vs. 3+/-2 ml, P<0.001), serum testosterone concentrations (78+/-34 vs. 49+/-20 ng per deciliter [2.7+/-1.2 vs. 1.7+/-0.7 nmol per liter], P=0.004), and serum inhibin B concentrations (119+/-52 vs. 60+/-21 pg per milliliter, P<0.001). Treatment with GnRH reversed the hypogonadism and restored fertility in each of the five men who received long-term therapy.
  
  
  CONCLUSIONS
  The recognition of adult-onset hypogonadotropic hypogonadism in men as a distinct disorder expands the spectrum of GnRH deficiency and identifies a treatable form of male infertility.
authors.affiliation: Reproductive Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: L B
authors.initials: LB
authors.lastname: Nachtigall
authors.forename: P A
authors.initials: PA
authors.lastname: Boepple
authors.forename: F P
authors.initials: FP
authors.lastname: Pralong
authors.forename: W F
authors.initials: WF
authors.lastname: Crowley
mesh_terms: D000328:Adult; D017668:Age of Onset; D007172:Erectile Dysfunction / Q000209:etiology; D007987:Gonadotropin-Releasing Hormone / Q000097:blood / Q000172:deficiency* / Q000627:therapeutic use; D006065:Gonadotropins, Pituitary / Q000097:blood; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000150:complications / Q000188:drug therapy; D007248:Infertility, Male / Q000188:drug therapy / Q000209:etiology*; D007265:Inhibins / Q000097:blood; D007989:Libido; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013737:Testis / Q000033:anatomy & histology; D013739:Testosterone / Q000097:blood
chemical_list: D006065:Gonadotropins, Pituitary; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007265:Inhibins