Effect of testosterone on insulin sensitivity, oxidative metabolism and body composition in aging men with type 2 diabetes on metformin monotherapy.

Abstract

AIMS:

To evaluate the effect of testosterone replacement therapy (TRT) on body composition, insulin sensitivity, oxidative metabolism and glycaemic control in aging men with lowered bioavailable testosterone (BioT) levels and type 2 diabetes mellitus (T2D) controlled on metformin monotherapy.

MATERIALS AND METHODS:

We conducted a randomized, double-blind, placebo-controlled study in 39 men aged 50-70 years with BioT levels <7.3 nmol/L and T2D treated with metformin monotherapy. Patients were randomized to testosterone gel (TRT, n = 20) or placebo (n = 19) for 24 weeks. Lean body mass (LBM), total and regional fat mass were measured using whole-body dual-energy X-ray absorptiometry scans. Whole-body peripheral insulin sensitivity, endogenous glucose production (EGP) and substrate oxidation were assessed by euglycaemic-hyperinsulinaemic clamp with glucose tracer and combined with indirect calorimetry. Coefficients (β) represent the placebo-controlled mean effect of intervention.

RESULTS:

LBM (β = 1.9 kg, p = 0.001) increased after TRT, while total fat mass (β = -1.3 kg, p = 0.009), fat mass trunk (β = -0.7 kg, p = 0.043), fat mass legs (β = -0.7 kg, p = 0.025), fat mass arms (β = -0.3 kg, p = 0.001), and HDL cholesterol (β = -0.11 mmol/L, p = 0.009) decreased after TRT compared with placebo. Insulin-stimulated glucose disposal rates did not change in response to TRT compared with placebo (p = 0.18). Moreover, glycated haemoglobin, and basal and insulin-stimulated rates of EGP, lipid- and glucose-oxidation were unaltered after TRT.

CONCLUSION:

TRT in aging men with lowered BioT levels and T2D controlled on metformin monotherapy improved body composition; however, glycaemic control, peripheral insulin sensitivity, EGP and substrate metabolism were unchanged.

• Authors: Line V Magnussen, Dorte Glintborg, Pernille Hermann, David M Hougaard, Kurt Højlund, Marianne Andersen
• Journal: Diabetes, obesity & metabolism (Diabetes Obes Metab) Vol. 18 Issue 10 Pg. 980-9 (10 2016) ISSN: 1463-1326 [Electronic] England
• PMID: 27265844 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: © 2016 John Wiley & Sons Ltd.

Chemical References

• Blood Glucose
• Insulin
• Placebos
• Testosterone
• Metformin

Topics

• Adult
• Aged
• Aging (blood, drug effects, physiology)
• Blood Glucose (drug effects, metabolism)
• Body Composition (drug effects)
• Diabetes Mellitus, Type 2 (complications, drug therapy, metabolism)
• Double-Blind Method
• Eunuchism (complications, drug therapy, metabolism)
• Hormone Replacement Therapy (adverse effects)
• Humans
• Insulin (metabolism)
• Insulin Resistance
• Male
• Metformin (therapeutic use)
• Middle Aged
• Oxidation-Reduction (drug effects)
• Placebos
• Testosterone (pharmacology, therapeutic use)
• Young Adult