title: Suppression of the high endogenous levels of plasma FSH in infertile men are associated with improved Sertoli cell function as reflected by elevated levels of plasma inhibin B.
abstract: BACKGROUND
  In vitro continuous stimulation of Sertoli cells with FSH leads to a desensitization of these cells to FSH action. To evaluate the presence of a desensitization of FSH receptor on Sertoli cells in vivo, we performed a controlled clinical study in 97 men affected by severe oligozoospermia.
  
  
  METHODS
  On the basis of FSH and inhibin B plasma concentrations, these subjects were divided into three groups: group A, 33 subjects with high FSH and low inhibin B plasma levels; group B, 32 subjects with high FSH plasma levels and inhibin B concentrations at the lower limit of the normal range; and group C, 32 subjects with normal FSH and inhibin B plasma levels. Patients with high FSH plasma levels (groups A and B) were prospectively randomized into two subgroups, called A1, A2, B1 and B2. Patients of groups A1 and B1 were treated with a GnRH agonist, leuprolide acetate, to induce a hypogonadotrophic state and then were treated with recombinant human FSH (r-hFSH; 100 IU/day) and hCG (2000 IU/twice a week) for 2 months. Subjects of groups A2, B2 and C were treated only with r-hFSH for the same period.
  
  
  RESULTS
  In patients of group A1, inhibin B remained unmodified during the whole period of study, whereas in subjects of group B1, we observed a significant reduction of this hormone during the hypogonadotrophic period and then an increase of inhibin B plasma levels that were higher that those observed before therapy. In patients of groups A2 and B2, FSH treatment did not induce a significant increase in inhibin B concentrations. In patients of group C, FSH induced a significant increase in inhibin B plasma levels.
  
  
  CONCLUSIONS
  In infertile men, suppression of the high endogenous levels of plasma FSH associated with much lower exogenous FSH levels is able to evoke higher inhibin B production, which may indicate improved Sertoli cell function and the possibility that this could have a positive effect on spermatogenesis.
authors.affiliation: Centre for Male Gamete Cryopreservation, Department of Medical and Surgical Sciences, Via Ospedale 105, 35128 Padova, Italy. carlo.foresta@unipd.it
authors.forename: C
authors.initials: C
authors.lastname: Foresta
authors.forename: A
authors.initials: A
authors.lastname: Bettella
authors.forename: D
authors.initials: D
authors.lastname: Spolaore
authors.forename: M
authors.initials: M
authors.lastname: Merico
authors.forename: M
authors.initials: M
authors.lastname: Rossato
authors.forename: A
authors.initials: A
authors.lastname: Ferlin
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000627:therapeutic use; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors* / Q000097:blood* / Q000627:therapeutic use; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists; D006801:Humans; D007248:Infertility, Male / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D007265:Inhibins / Q000097:blood*; D016729:Leuprolide / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009994:Osmolar Concentration; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000627:therapeutic use; D012708:Sertoli Cells
chemical_list: D006063:Chorionic Gonadotropin; D011994:Recombinant Proteins; C422364:inhibin B; D007987:Gonadotropin-Releasing Hormone; D007265:Inhibins; D005640:Follicle Stimulating Hormone; D016729:Leuprolide