Testosterone increases muscle sympathetic nerve activity in young healthy males

Abstract

A positive correlation between levels of testosterone and muscle sympathetic nerve activity (MSNA) has been found in women with polycystic ovarian syndrome, and is associated with cardiovascular risk factors. However, testosterone has been shown to be cardio‐protective in male rats. To date, we are unaware of any studies that have tested the direct impact of testosterone administration on MSNA in young, healthy males. The purpose of the current study was to examine the acute effects of short‐term testosterone administration on MSNA on this demographic.MethodsMSNA (via microneurography), heart rate, and beat‐by‐beat blood pressure were recorded following a venous blood draw for baseline testosterone levels in four young, healthy male subjects. After assessing resting measures, each subject self‐administered 120 mg/day of transdermal testosterone for seven days and were then retested. We analyzed MSNA frequency (bursts min−1) and incidence (bursts 100 heartbeats−1).ResultsTestosterone level increased in all subjects (676±47 ng/dl to 774±16 ng/dl). Increased levels of total testosterone tended to increase MSNA frequency, (11±3 to 15±1, p=0.10) and incidence (22±4 to 27±3, p=0.18).ConclusionShort‐term, transdermal testosterone administration tends to increase MSNA frequency and incidence in young, healthy males. Supported by NIH Grant HL081671.