sterolrelated

Sterol-related refers to properties, processes, and compounds associated with sterols, a subclass of steroids characterized by a hydroxyl group at C3 and a fused ring system. The term encompasses the chemistry, biosynthesis, regulation, and physiological roles of sterols in living organisms. Major examples include cholesterol in animals; ergosterol in fungi; and plant phytosterols such as sitosterol and stigmasterol. Sterols are essential components of eukaryotic cell membranes, helping to modulate fluidity and permeability and to organize lipid microdomains. They also serve as precursors for bile acids and steroid hormones in animals, and in plants and fungi participate in signaling and development.

Biosynthesis of sterols proceeds primarily via the mevalonate pathway, yielding isoprenoid units that are assembled into squalene and cyclized to form the sterol nucleus. In animals and fungi this nucleus becomes lanosterol, subsequently converted to cholesterol or ergosterol; in plants the cyclization product is cycloartenol. Enzyme regulation, notably HMG-CoA reductase, controls flux through the pathway, and feedback from sterol levels maintains homeostasis. Dietary sterols influence human health: plant sterols can reduce LDL cholesterol absorption, while excess cholesterol is linked to cardiovascular disease. Genetic disorders of sterol metabolism include Smith-Lemli-Opitz syndrome (DHCR7 deficiency) with reduced cholesterol and elevated 7-dehydrocholesterol, and sitosterolemia (ABCG5/ABCG8 defects) leading to accumulation of dietary plant sterols.

Analytically, sterol-related research employs chromatography and mass spectrometry to profile sterol composition in tissues, while biotechnological applications explore engineered sterol pathways for crop improvement and industrial enzymes for sterol modification.