Effect of testosterone on insulin sensitivity in men with idiopathic hypogonadotropic hypogonadism.
OBJECTIVE
To assess the presence of insulin resistance (IR) among a homogeneous cohort of male patients with idiopathic hypogonadotropic hypogonadism (IHH) and to investigate the effects of testosterone therapy on IR in this specific group.


METHODS
Twenty-four male patients with untreated IHH and 20 age-, sex-, and weight-matched eugonadal healthy control subjects were recruited for the study. Plasma glucose, plasma insulin, total and free testosterone, follicle-stimulating hormone, luteinizing hormone, estradiol, and sex hormone-binding globulin levels were measured in fasting blood samples, and biochemical and hormonal analyses were performed for all study participants. IR was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) formula and the quantitative insulin sensitivity check index (QUICKI). Body mass index was calculated by weighing and measuring the heights of all study participants at the beginning of the investigation. Body fat mass and body lean mass were calculated as percentages of body weight by bioelectrical impedance analysis of body composition. Sustanon 250 (a combination of 4 testosterones) was administered intramuscularly once every 3 weeks for 6 months to male patients with IHH after a basal anthropometric, biochemical, and hormonal evaluation. The response to therapy was monitored by regular clinical examinations and serum testosterone measurements. After 6 months of testosterone treatment, the entire anthropometric, biochemical, and hormonal evaluation was repeated 14 days after the last injection of testosterone.


RESULTS
Before treatment, male patients with IHH had higher fasting plasma glucose concentrations, higher fasting plasma insulin levels, a higher HOMA-IR score, and a lower QUICKI when compared with the control group. After testosterone treatment in the patient group, the HOMA-IR score decreased dramatically to the level in the control group. The high body fat mass of the male patients with IHH was reduced significantly after testosterone treatment, concomitant with significant increases in body mass index and body lean mass.


CONCLUSIONS
Insulin sensitivity improves and body fat mass decreases with long-term testosterone replacement therapy.
Naharci
Mehmet Ilkin
MI
Department of Internal Medicine, Gulhane School of Medicine, Etlik, Ankara, Turkey.
Pinar
Murat
M
Bolu
Erol
E
Olgun
Abdullah
A
D000328:Adult; D001823:Body Composition / Q000187:drug effects; D015992:Body Mass Index; D001835:Body Weight / Q000187:drug effects; D016022:Case-Control Studies; D004958:Estradiol / Q000097:blood; D005215:Fasting / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000097:blood; D020249:Hormone Replacement Therapy; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D007333:Insulin Resistance / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D016896:Treatment Outcome
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone