Mineralocorticoid synthesis aldosterone pregnenolone produced biosynthesis of steroid hormones the adrenal steroid hormones are synthesized from cholesterol which is mostly derived lchsreunionfo
If the plasma cortisol level is below the normal range (i.e., less than 5 ^g/dl), the operation has been successful, and steroid replacement therapy will be required until the hypothalamic-pituitary-adrenal (HPA) axis can recover—possibly 1 year or longer. During this period, the patient should be treated with hydrocortisone at a rate of 12 mg/m2 in a single daily dose with breakfast. Adrenal function is tested with a synthetic ACTH (cosyntropin) stimulation test at 3-month intervals. In patients with cortisol values between 5 and 20 ^.g/dl after cosyntropin stimulation, cortisol replacement therapy can be withdrawn; but 3-month testing should continue, and cortisol replacement therapy should be reinstituted if signs and symptoms of adrenal insufficiency appear. As soon as the cortisol level reaches 20 ^.g/dl or greater after cosyntropin stimulation, discontinuance of cortisol replacement without continued testing is safe.
The Ups and Downs of Cortisol: What You Need to …
Differential diagnostic tests will generally show ACTH-inde-pendent Cushing syndrome associated with increased serum testosterone levels in hirsute or virilized women. Occasionally, increased serum estradiol levels will be found in feminized men with Cushing syndrome. In rare instances, patients will present with virilization or feminization only, and some will have hypertension caused by tumor secretion of aldosterone precursors. CT or MRI scans usually show a large unilateral adrenal mass. Masses greater than 6 cm have a greater chance of being malignant. These tumors tend to be large when first discovered because the adrenal steroidogenic cells, in the course of dedifferen-tiation, become less efficient in cortisol synthesis. As a result, the tumor burden has to be large to yield the same clinical effect as a small, highly differentiated, benign adenoma.