Another important aspect to consider is how your current medications might be affecting your adrenals in a negative way. It’s possible that adrenal insufficiency can develop when a person taking glucocorticoid hormones (like prednisone) for a long time, which act similarly to cortisol, suddenly stops taking those medications. If you’re on any prescriptions for treating inflammatory illnesses like rheumatoid arthritis, asthma or ulcerative colitis , talk to your doctor about how to adjust your dosage appropriately before changing them yourself since these can lower ACTH and cortisol.
The human genome includes approximately 20,000 protein coding genes and 70% of these genes are expressed in the normal, adult adrenal glands.   Only some 250 genes are more specifically expressed in the adrenal glands compared to other organs and tissues. The adrenal gland specific genes with highest level of expression include members of the cytochrome P450 superfamily of enzymes. Corresponding proteins are expressed in the different compartments of the adrenal gland, such as CYP11A1 , HSD3B2 and FDX1 involved in steroid hormone synthesis and expressed in cortical cell layers, and PNMT and DBH involved in noradrenalin and adrenalin synthesis and expressed in the medulla.