Cholesterol is often associated with arteriosclerosis and other cardiovascular diseases. However, this four-ring carbon compound is an important structural element of cells, playing a key role in the synthesis of bile acids in the liver and vitamin D in skin, according to the Proceedings of the National Academy of Sciences of the United States of America (PNAS).
Steroid hormones have a four-ring carbon structure and include estrogens (sexual female hormones), testosterone (a male hormone), and progesterones, which are involved in the menstrual cycle and pregnancy. According to Sharon Rady Rolfes in "Understanding Normal and Clinical Nutrition," cortisol and aldosterone are also four-ring carbon steroid hormones. Cortisol is produced in the adrenal gland and is released in response to stress and low blood glucose. Aldosterone regulates sodium and potassium balance in the kidneys.
Dexamethasone is a synthetic hormone used to treat inflammatory arthritis and some allergies and to avoid nausea and vomiting during cancer chemotherapy. Dexamethasone is administered by intravenous or intramuscular injection, inhalation, or directly applied to the skin, according to the website Chemicalland 21. Dexamethasone is also used in the treatment of cerebral edema, endocrine, ophthalmic, and renal and respiratory diseases, according to Drug Information Online.