Introduction

Cholesterol is an essential component of the cell membrane of all animal cells. Cholesterol forms the basis for the synthesis of steroid hormones such as aldosterone, cortisone and testosterone; it also essential for development of the embryo. Although part of the cholesterol present in the human body is derived from the diet, it is mostly produced in the liver and used largerly for bile production. As cholesterol, like all lipids, is insoluble in the blood, aggregated complexes such as lipoproteins are used for its transportation in circulation. For this reason, when in medicine the term "cholesterol" is used, reference is in fact being made to lipoproteins which circulate in the blood, the concentration of which is known as cholesterolemia.