The cortex is the part of the adrenal gland that makes cortisol Cortisol - a glucocorticoid that controls glucose production and suppresses the immune system , a hormone that is crucial for life. If the patient does not have enough adrenal cortex left, he or she may develop adrenal insufficiency and may need to take steroid medication. ( See What are the potential complications? ) In cases of bilateral adrenal tumors (. a tumor in both adrenal glands) or tumors that are small and clearly not cancer (like aldosterone Aldosterone - a mineralocorticoid that controls blood pressure producing adenomas), some surgeons may perform a cortical-sparing adrenalectomy Cortical-sparing adrenalectomy - an operation to remove the part of an adrenal gland that has the tumor. Also called a partial adrenalectomy. to keep as much of this normal cortex as possible. This usually involves looking at the entire adrenal gland and cutting out just the tumor with a thin rim of normal tissue.
Glucocorticoids are potent anti-inflammatories, regardless of the inflammation's cause; their primary anti-inflammatory mechanism is lipocortin-1 (annexin-1) synthesis. Lipocortin-1 both suppresses phospholipase A2 , thereby blocking eicosanoid production, and inhibits various leukocyte inflammatory events ( epithelial adhesion , emigration , chemotaxis , phagocytosis , respiratory burst , etc.). In other words, glucocorticoids not only suppress immune response, but also inhibit the two main products of inflammation, prostaglandins and leukotrienes . They inhibit prostaglandin synthesis at the level of phospholipase A2 as well as at the level of cyclooxygenase /PGE isomerase (COX-1 and COX-2),  the latter effect being much like that of NSAIDs , potentiating the anti-inflammatory effect.
As a mitochondrial P450 system, P450c11 is dependent on two electron transfer proteins, adrenodoxin reductase and adrenodoxin that transfer 2 electrons from NADPH to the P450 for each monooxygenase reaction catalyzed by the enzyme. In most respects this process of electron transfer appears similar to that of P450scc system that catalyzes cholesterol side chain cleavage.  Similar to P450scc the process of electrons transfer is leaky leading to superoxide production. The rate of electron leakage during metabolism depends on the functional groups of the steroid substrate.