title: Effect of a single injection of testosterone enanthate on 17β estradiol and bone turnover markers in hypogonadal male patients.
abstract: OBJECTIVE
  Several clinical studies testify the critical role played by estrogens in male bone metabolism. The aim of our study is to assess the effect of a single injection of testosterone enanthate in a group of hypogonadal men on 17β estradiol serum levels and some bone metabolic parameters.
  
  
  METHODS
  Twenty-one hypogonadal males were given one testosterone enanthate injection (250 mg). Blood samples were drawn before the injection and after 1, 2 and 3 weeks. The following variables were measured: Total testosterone (TT), 17β estradiol (17β E2), Sex hormone binding globulin, total alkaline phosphatase, osteocalcin, and C-telopeptide of type I collagen (CTx).
  
  
  RESULTS
  After testosterone injection, both TT and 17β E2 increased, peaking 1 week after the injection. Individual observation of the response of 17β E2 to testosterone showed that a subgroup (n = 9) failed to respond with any increase in 17β E2 at any of the weekly tests (group E2-), while the remainder (n = 12) showed a significant increase in 17β E2, which reached a mean value three times higher than at baseline (group E2+). The E2- patients reached a TT peak lower than that observed in the E+ group. CTx serum levels declined progressively in the E2+ group, reaching the significance (p = 0.03) at the end of the study, while it did not change in E- group.
  
  
  CONCLUSIONS
  This study suggests that a single injection of testosterone might have different effects on the production of endogenous estrogens, and a significant reduction of bone resorption parameters takes place only in the patients who show a significant increase of 17ß estradiol in response to testosterone administration.
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. valentina.camozzi@unipd.it.
authors.forename: V
authors.initials: V
authors.lastname: Camozzi
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. guglielmo.bonanni@unipd.it.
authors.forename: G
authors.initials: G
authors.lastname: Bonanni
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, Unit of Biostatistics, Epidemiology and Public Health, University of Padova, via Loredan 18, 35131, Padua, Italy. annachiara.frigo@unipd.it.
authors.forename: A
authors.initials: A
authors.lastname: Frigo
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. michele.piccolo@unipd.it.
authors.forename: M
authors.initials: M
authors.lastname: Piccolo
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. sergio.ferasin@unipd.it.
authors.forename: S
authors.initials: S
authors.lastname: Ferasin
authors.affiliation: Department of Medical Laboratory, University of Padova, via Giustiniani 2, 35128, Padua, Italy. martina.zaninotto@sanita.padova.it.
authors.forename: M
authors.initials: M
authors.lastname: Zaninotto
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. marco.boscaro@unipd.it.
authors.forename: M
authors.initials: M
authors.lastname: Boscaro
authors.affiliation: Department of Medicine, Unit of Endocrinology, University of Padova, via Ospedale 105, 35128, Padua, Italy. giovanni.luisetto@unipd.it.
authors.forename: G
authors.initials: G
authors.lastname: Luisetto
mesh_terms: D000328:Adult; D000728:Androgens / Q000008:administration & dosage / Q000494:pharmacology*; D015415:Biomarkers / Q000097:blood; D016723:Bone Remodeling / Q000187:drug effects*; D004958:Estradiol / Q000097:blood*; D006801:Humans; D007006:Hypogonadism / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D013739:Testosterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood* / Q000494:pharmacology
chemical_list: D000728:Androgens; D015415:Biomarkers; D013739:Testosterone; D004958:Estradiol; C004648:testosterone enanthate
keywords: Bone metabolism; Bone turnover markers; Estrogens; Hypogonadism; Testosterone