The link between low testosterone and decreased insulin sensitivity had been shown in previous research.
A known link between low testosterone levels and decreased insulin sensitivity could lead to a treatment for men with type 2 diabetes, according to a study just published in the journal Diabetes Care.
A team of researchers from the Jacobs School of Medicine at the University of Buffalo, NY, had previously shown this link, and had also observed a similar connection in one-third of men in a study who had T2D and were also obese.
In the current study, researchers recruited 94 men with T2D who were divided into 2 groups: 44 had low testosterone levels, and 50 did not. Researchers calculated insulin sensitivity and measured lean body mass and fat mass with magnetic resonance imagining (MRI) and dual-energy X-ray absorptiometry (DXA). Subcutaneous fat samples were taken to assess insulin signaling genes.
The 44 men with low testosterone levels had higher subcutaneous and visceral fat levels than the 50 men with normal testosterone levels. The low-testosterone men were randomized to receive a 250 mg injection of testosterone or placebo every 2 weeks for 24 weeks. The treatment did not change their body weight, but it did reduce body fat by 3 kg (more than 6 pounds), and muscle mass increased.
Insulin sensitivity increased as well; there was a 32% increase in glucose uptake in tissues in response to insulin, an increase in lean mass and a decrease in subcutaneous fat mass, compared with those men who took the placebo.
The expression of insulin signaling genes (IR-B, IRS-1, AKT-2, and GLUT4) in adipose tissue was lower in men with low testosterone levels before treatment began, and upregulated after the treatment.
According to study’s corresponding author, Paresh Dandona, MD, this study is the first to show testosterone’s sensitizing effects on insulin; thus, it is a metabolic hormone.
Dhindsa S, Ghanim H, Batra M, et al. Insulin resistance and inflammation in hypogonadotropic hypogonadism and their reduction after testosterone replacement in men with type 2 diabetes [published online November 29, 2015]. Diabetes Care. 2015; doi:10.2337/dc15-1518