The cells either produce their own cholesterol or take up LDL circulating in the blood stream. The discovery of the LDL-receptor by Brown and Goldstein in 1973 was a milestone in cholesterol research. Several hormones are produced from cholesterol like estrogen and testosteron, cortison and aldactone. Cholesterol is stored in cells of the adrenals and gonads and can be utilized as soon as there is a requirement for these hormones. Cholesterol also takes part in the synthesis of vitamin D which prevents development of rickets.
Vitamin D is produced in the skin when exposed to the sun's ultraviolet light.
Another vital function of cholesterol is associated with food intake. Cholesterol is converted into bile acids in the liver and is transported via the bile to the upper intestine where the bile salts emulsify the dietary fat making it absorbable. The bile salts then return to the blood stream and are taken up by the liver and again secreted into the upper intestine. This recycling of bile acids normally limits the liver's need for cholesterol. As stated above cholesterol is of vital importance for the body.