{Reference Type}: Journal Article
{Title}: Testosterone with dutasteride, but not anastrazole, improves insulin sensitivity in young obese men: a randomized controlled trial.
{Author}: Juang PS;Peng S;Allehmazedeh K;Shah A;Coviello AD;Herbst KL;
{Journal}: J Sex Med
{Volume}: 11
{Issue}: 2
{Year}: Feb 2014
{Factor}: 3.937
{DOI}: 10.1111/jsm.12368
{Abstract}: <B>BACKGROUND: </B>Testosterone (T) administration to men increases T, estradiol (E2), dihydrotestosterone (DHT), and fat-free mass (FFM), and decreases fat mass (FM) but does not consistently improve insulin sensitivity (IS).<BR><B>OBJECTIVE: </B>The aim of this study was to examine the effects of T administration in obese, nondiabetic men on body composition and IS, and to determine if inhibition (i) of metabolism of T to E2 with anastrazole or to DHT with dutasteride alters these effects.<BR><B>METHODS: </B>This was a 98-day randomized, double-blind, parallel group, placebo-controlled trial of 57 men, 24-51 year, free T in the lower 25% of normal range (<0.33 nmol/L), body mass index ≥ 30.0 kg/m(2). Subjects were randomized to one of four groups: (i) placebo: gel, pills, and injection; (ii) T/DHT/iE2: T gel, anastrazole, and acyline (gonadotropin releasing-hormone antagonist to suppress endogenous T); (iii) T/iDHT/E2: T gel, dutasteride, and acyline; (iv) T/DHT/E2: T gel, placebo pills, and acyline.<BR><B>METHODS: </B>Main outcome measures are insulin sensitivity as percent change (%Δ) in glucose disposal rates (GDR) from a two-step euglycemic clamp (GDR1 and 2), and %FM and %FFM by dual X-ray absorptiometry scan.<BR><B>RESULTS: </B>Insulin Sensitivity: %Δ GDR1 differed across groups (P = 0.02, anova) and was significantly higher in the dutasteride (T/iDHT/E2) compared with the placebo and T gel (T/DHT/E2) groups. %ΔGDR2 was higher in the dutasteride (T/iDHT/E2) compared with the anastrazole (T/DHT/iE2) group. Body Composition: T gel alone (T/DHT/E2) or with dutasteride (T/iDHT/E2) significantly increased %FFM (P < 0.05) and decreased %FM (P < 0.05). There was no change in %FFM or %FM after placebo or anastrazole (T/DHT/iE2).<BR><B>CONCLUSIONS: </B>The combination of T plus dutasteride improved body composition and IS while T alone improved body composition but not IS, suggesting that when T is administered to men, reduction to DHT attenuates the beneficial effects of aromatization to E2 on IS but not body composition.