[Fatty acids--2. Clinical and physiological significance].

Fatty acids play multiple roles in humans and other organisms. In triglycerides they are the source of metabolic energy, in adipose tissue they serve also as temperature and mechanical isolators, in the form of phospholipids they are structural components of membranes. Fatty acids originating from the sn-2 glycerol carbon of phosphatidylcholine can influence the activity of diglycerides as second messengers. Unsaturated FA with 18-20 carbon atoms are precursors of prostaglandins, leucotrienes and thromboxanes, which have a broad scale of regulatory properties and have autocrine as well as paracrine effects. Fatty acids are ligands of several nuclear receptors, which take part in the subcellular control of a number of metabolic pathways. Covalent modification of proteins by FA (acylation) enables FA incorporation into the membranes. Number of pathological stages is accompanied with changes in fatty acid composition, often expressed as decreased content of unsaturated and increased content of saturated fatty acids (e.g. dyslipidemia, malnutrition, inflammation and inherited diseases). Polyunsaturated fatty acids as dietary supplements are used in prevention and in the therapy of cardiovascular diseases and other metabolic disturbances.