Ovarian hormone loss modifies the nucleic acid cargo of circulating extracellular vesicles and skeletal muscle metabolism after acute exercise in rats.

Loss of ovarian hormones (i.e., menopause) leads to negative effects on metabolic health. While exercise offers significant benefits, it seems to be insufficient to completely reverse these changes. The mechanisms by which exercise conveys the effects throughout the body are still poorly understood. Extracellular vesicles (EVs) are released into circulation during exercise. EVs carry small non-coding RNAs (sRNAs), such as microRNAs (miRs), which are proposed as mediators of the effects of exercise. We have previously shown that the miR response to acute exercise of EVs and high-density lipoprotein (HDL) is diminished in postmenopausal women with low oestrogen levels, which we were able to replicate here also in a rat model. In this study, we examined the effect of loss of ovarian hormones and acute exercise in the sRNA cargo of EV and HDL particles in female rats. We show for the first time that loss of ovarian hormones affects specifically the nucleic acid cargo of circulating EVs. We further show that the oestrogen responsive miRs regulate anaerobic glycolytic pathway. Finally, we demonstrate that the loss of ovarian hormones leads to higher anaerobic energy production during an acute bout of exercise, implicating an inferior ability to sustain aerobic energy production during exercise.