Endocrine disease and glucocorticoid treatment: Cognitive and emotional function
Given the central role that MR and GR play in cognitive and emotional processes as outlined above, it is not surprising that endocrine diseases and long-term steroid treatment are associated with alterations in these processes. While it is often difficult to exactly disentangle MR vs. GR-mediated effects, it is increasingly becoming clear that the MR has an important role in these effects. The support for MR directly effecting mood states stems from the use of potent synthetic glucocorticoids in the clinic, which are accompanied by adverse psychological, behavioural, and cognitive effects (Fardet, Petersen and Nazareth, 2012; Judd et al. , 2014). Dexamethasone (DEX) is an example of such potent synthetic GCs and is in vivo highly selective for GR (Reul et al. , 2000). This strong activation of GR by DEX causes suppression of HPA axis activity leading to a reduction in cortisol levels and consequently depletes MR of its ligand. As such, it is thought that this aberrant increase and decrease in GR and MR activity, respectively, causes disturbances in system homeostasis regulated by the two receptors (Meijer and de Kloet, 2017).