2025年1月13日 · A steroid is any of a class of natural or synthetic organic compounds characterized by a molecular structure of 17 carbon atoms arranged around four rings. Steroids are important in biology, chemistry, and medicine.

2025年1月13日 · All steroids are related to a characteristic molecular structure composed of 17 carbon atoms—arranged in four rings conventionally denoted by the letters A, B, C, and D—bonded to 28 hydrogen atoms.

2025年1月13日 · The molecular structures of metabolites of cholesterol form an evolutionary series from the bile alcohols, such as myxinol and scymnol of the elasmobranch fishes (e.g., sharks and rays) and the related alcohols of some bony fishes and frogs, through the 5β-cholestanoic acids of crocodiles and alligators, to the 5β-cholanoic acids of the birds ...

2025年1月13日 · Abundant data for the behaviour of steroids in paper chromatography, thin-layer chromatography, liquid chromatography, and gas-liquid chromatography show that individual features of molecular structure determine the chromatographic properties of steroids in a predictable manner.

Steroid hormones are secreted by three glands—the adrenal cortex, testes, and ovaries—and by the placenta during pregnancy. Learn more about steroid hormone classification, secretion, and function.

2025年1月4日 · Lipid-derived hormones, known as steroid hormones, are important chemical messengers and include testosterone and estrogens. At an organismal level triglycerides stored in adipose cells serve as energy-storage depots and also provide thermal insulation.

2025年1月4日 · The characteristic feature of each of these three important molecules is four rigidly fused carbon rings forming the steroid nucleus and a hydroxyl (OH) group attached to the first ring. One molecule is distinguished from another by the positions of the carbon-carbon double bonds and by the structure of the hydrocarbon side chain on the fourth ...

Steroids, a class of compounds of great importance in both plants and animals, are not isoprenoids but are derived directly from them. Uses of isoprenoids. Of the uses that humans have found for isoprenoids, many were established in antiquity—as ingredients of perfumes and incense, flavourings and spices, and varnishes and medicinals.

2024年12月24日 · Chemically, cholesterol is an organic compound belonging to the steroid family; its molecular formula is C 27 H 46 O. In its pure state it is a white, crystalline substance that is odourless and tasteless.

This parent structure (1), named gonane (also known as the steroid nucleus), may be modified in a practically unlimited number of ways by removal, replacement, or addition of a few atoms at a time; hundreds of steroids have been isolated from plants and animals, and thousands more have been prepared…