Hypothalamic Gliosis by MRI and Visceral Fat Mass Negatively Correlate with Plasma Testosterone Concentrations in Healthy Men

Objective This study aimed to determine whether a relationship was evident between gliosis in the mediobasal hypothalamus (MBH) and plasma testosterone concentrations in men. Methods A total of 41 adult men (aged 18‐50 years) from 23 twin pairs underwent fasting morning blood draw and brain magnetic resonance imaging. T2 relaxation time was used to quantify gliosis in the MBH and control areas in the putamen and amygdala. Plasma concentrations of testosterone and 17β‐estradiol were measured by liquid chromatography‐tandem mass spectrometry. Body composition including visceral adiposity was measured by dual x‐ray absorptiometry. Results A negative association was found between MBH T2 relaxation time and plasma concentrations of both free and total testosterone (r = −0.29, P