Thyroid, adrenal and other hormones also regulate cell excitability. Cortisol is a hormone secreted by the cortex of the adrenal glands. Addison's disease is an endocrine disease that results from hypocortisolism caused by adrenal gland insufficiency. The natural steroid hormones are generally synthesized from cholesterol in the gonads and adrenal glands. A number of endocrine diseases involve dysfunctions of the adrenal gland. The main corticosteroids produced by the adrenal cortex are cortisol and aldosterone. Cushing's disease and Addison's disease are pathologies involving the dysfunction of the adrenal gland. There was also damage to the adrenal glands and pancreas. The adrenal cortex is the outermost layer of the adrenal gland. It also occurs in the zona reticularis of the adrenal gland. Other causes include certain medications, sepsis, and bleeding into both adrenal glands. Scintigraphy of the adrenal gland with iodocholesterol scan is occasionally necessary. Hormone replacement is standard for ALD patients demonstrating adrenal insufficiency. Aldosterone is a mineralocorticoid which is synthesized in the adrenal glands. It is used to check the function of the ovaries, placenta, adrenal glands.