The biological effects of 5G electromagnetic fields on living organisms are poorly understood. Studies suggested that exposure to radio frequencies, and notably 2G fields (900MHz), may alter the structure and function of the adrenal glands, impacting hormonal response to stress. The effect of 5G fields (3.5GHz) on these mechanisms, however, is not known.

To assess the impact of exposure to 2G and 5G electromagnetic fields on the expression of genes involved in the adrenal stress response in rats at different developmental stages.

Male Wistar rats were divided into 2 age groups: juveniles (3 weeks) and young adults (8 weeks). They were exposed to 900MHz (2G) and 3.5GHz (5G) electromagnetic fields at an intensity of 1.5V/m in 2 daily 1-hour sessions, for 2 weeks. Expression of adrenal stress genes (CH25H and StAR) and corticosteroidogenic enzymatic cofactors (CYP-11a1, CYP-21a1 and HSD-3b1) was assessed on RT-qPCR.

No significant changes in transcriptomic expression were observed, whatever the developmental stage or exposure intensity. Grouping the animals by exposure condition revealed no significant effect of electromagnetic fields on the adrenal markers studied (Fig. 1).

Contrary to some studies suggesting an effect of radio frequencies on adrenal function, in the present study 2-week exposure to 5G or 2G fields did not alter the expression of stress genes. It would be useful to explore longer exposure and higher intensity to assess possible long-term effects and reproduce real-life conditions of exposure to electromagnetic fields.