Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.29.227330v1?rss=1 Authors: Romano, N., Duncan, P., McClafferty, H., Nolan, O., Ding, Q., Homer, N. Z., Le Tissier, P., Walker, B. R., Shipston, M. J., Chambers, T. J. G. Abstract: Glucocorticoids (GC) are prescribed for periods >3 months to 1-3% of the UK population; 10-50% of these patients develop hypothalamus- pituitary-adrenal (HPA) axis suppression, which may last over 6 months and is associated with morbidity and mortality. Recovery of higher nodes of the axis is necessary for recovery of adrenal function. We developed a mouse model of Dexamethasone (DEX)-induced HPA axis dysfunction in order to further explore recovery in the pituitary. Adult male C57BL6/J or those crossed with Pomc-eGFP mice were randomly assigned to receive DEX (~0.4 mg/kg bodyweight/day) or vehicle via drinking water for 4 weeks following which treatment was withdrawn. Tissues were harvested at 0, 1, and 4 weeks following withdrawal of treatment. Corticotrophs were isolated from Pomc-eGFP pituitaries using FACS, and RNA extracted for RNA-seq. DEX treatment suppressed corticosterone production, which remained partially suppressed at least 1 week following DEX withdrawal. In the adrenal, at time 0, Hsd3b2, Cyp11a1, and Mc2r mRNA levels were significantly reduced, with Mc2r and Cyp11a1 remaining reduced 1 week following DEX withdrawal. The corticotroph transcriptome was modified by DEX treatment with some differences between groups persisting 4 weeks following withdrawal. No genes supressed by DEX exhibited ongoing attenuation 1 and 4 weeks following withdrawal, whilst only 2 genes were upregulated and remained so following withdrawal. A pattern of rebound at 1 and 4 weeks was observed in 14 genes that increased following suppression, and 6 genes that were reduced by DEX and then increased. Chronic GC treatment may induce persistent changes in the pituitary that may influence future response to GC treatment or stress. Copy rights belong to original authors. Visit the link for more info