title: Testosterone replacement therapy restores normal ghrelin in hypogonadal men.
abstract: We recently described a connection between androgens and ghrelin in women affected by the polycystic ovary syndrome. To further investigate the interaction between sex steroids and ghrelin, we investigated circulating ghrelin levels in a group of hypogonadal men before and after therapeutic intervention aiming at normalization low testosterone (T) concentrations. Seven hypogonadal men were compared with nine overweight/moderately obese men matched for body mass index and body fat distribution parameters, as well as with 10 normal weight controls. Total and free T and plasma ghrelin levels were significantly lower in the hypogonadal men than in the control groups. Hypogonadal men also had a significantly higher insulin resistance state. Ghrelin levels were positively correlated with both total and free T concentrations. A significant correlation was also found between ghrelin and the anthropometric parameters and the insulin resistance indexes. However, in a multiple regression analysis in which a correction for all covariants was performed, only the relationship with total and free T persisted. After the 6-month replacement T therapy, ghrelin levels of hypogonadal patients increased and did not differ significantly in comparison with both control groups. The positive correlation between ghrelin and androgens still persisted after T replacement therapy, after adjusting for confounding variables. These data further indicate that sex hormones modulate circulating ghrelin concentrations in humans. This may be consistent with the concept that ghrelin may exert a relevant role in the endocrine network connecting the control of the reproductive system with the regulation of energy balance.
authors.affiliation: Endocrine Unit, Department of Internal Medicine and Gastroenterology, and Center for Applied Biomedical Research, Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy 40138.
authors.forename: Uberto
authors.initials: U
authors.lastname: Pagotto
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gambineri
authors.forename: Carla
authors.initials: C
authors.lastname: Pelusi
authors.forename: Silvia
authors.initials: S
authors.lastname: Genghini
authors.forename: Mauro
authors.initials: M
authors.lastname: Cacciari
authors.forename: Baerbel
authors.initials: B
authors.lastname: Otto
authors.forename: Tamara
authors.initials: T
authors.lastname: Castañeda
authors.forename: Matthias
authors.initials: M
authors.lastname: Tschöp
authors.forename: Renato
authors.initials: R
authors.lastname: Pasquali
mesh_terms: D000328:Adult; D000886:Anthropometry; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects; D054439:Ghrelin; D006706:Homeostasis / Q000502:physiology; D020249:Hormone Replacement Therapy; D006728:Hormones / Q000097:blood; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000188:drug therapy*; D007328:Insulin / Q000097:blood; D007713:Klinefelter Syndrome / Q000097:blood / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism; D036361:Peptide Hormones / Q000097:blood*; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood / Q000627:therapeutic use*
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D006728:Hormones; D007328:Insulin; D036361:Peptide Hormones; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone