By function The major classes of<unk>  hormones, with prominent members and examples of related functions, are: * Corticosteroids: * Glucocorticoids: * Cortisol, a glucocorticoid whose functions include immunosuppression * Mineralocorticoids: * Aldosterone, a mineralocorticoid which helps regulate blood pressure through water and electrolyte balance * Sex<unk> s: * Progestogens: * Progesterone, which regulates cyclical changes in the endometrium of the uterus and maintains a pregnancy * Androgens: * Testosterone, which contributes to the development and maintenance of male secondary sex characteristics * Estrogens: * Estradiol, which contributes to the development and maintenance of female secondary sex characteristics Additional classes of<unk> s include: * Neurosteroids such as and allopregnanolone * Bile acids such as taurocholic acid * Aminosteroid neuromuscular blocking agents (mainly synthetic) such as pancuronium bromide *<unk> al antiandrogens (mainly synthetic) such as cyproterone acetate *<unk> ogenesis inhibitors (mainly exogenous) such as alfatradiol * Membrane sterols such as cholesterol, ergosterol, and various phytosterols * Toxins such as<unk> al saponins and cardenolides/cardiac glycosides As well as the following class of secosteroids (open-ring<unk> s): * Vitamin D forms such as ergocalciferol, cholecalciferol, and calcitriol By structure Intact ring system<unk> s can be classified based on their chemical composition. One example of how MeSH performs this classification is available at the Wikipedia MeSH catalog. Examples of this classification include: Cholecalciferol (vitamin D), an example of a 9,10-secosteroid Cyclopamine, an example of a complex C-nor-D-homosteroid Class Example Number of carbon atoms Cholestanes Cholesterol 27 Cholanes Cholic acid 24 Pregnanes Progesterone 21 Androstanes Testosterone 19 Estranes Estradiol 18 In biology, it is common to name the above<unk>  classes by the number of carbon atoms present when referring to hormones: C18-steroids for the estranes (mostly estrogens), C19-steroids for the androstanes (mostly androgens), and C21-steroids for the pregnanes (mostly corticosteroids). The classification "17-ketosteroid" is also important in medicine. The gonane<unk>  nucleus) is the parent 17-carbon tetracyclic hydrocarbon molecule with no alkyl sidechains. Cleaved, contracted, and expanded rings Secosteroids (Latin seco, "to cut") are a subclass of<unk> al compounds resulting, biosynthetically or conceptually, from scission (cleavage) of parent<unk>  rings (generally one of the four). Major secosteroid subclasses are defined by the<unk>  carbon atoms where this scission has taken place. For instance, the prototypical secosteroid cholecalciferol, vitamin D3 (shown), is in the 9,10-secosteroid subclass and derives from the cleavage of carbon atoms C-9 and C-10 of the<unk>  B-ring; 5,6-secosteroids and 13,14-steroids are similar. Norsteroids (nor-, L. norma; "normal" in chemistry, indicating carbon removal) and homosteroids (homo-, Greek homos; "same", indicating carbon addition) are structural subclasses of<unk> s formed from biosynthetic steps. The former involves enzymic ring expansion-contraction reactions, and the latter is accomplished (biomimetically) or (more frequently) through ring closures of acyclic precursors with more (or fewer) ring atoms than the parent<unk>  framework. Combinations of these ring alterations are known in nature. For instance, ewes who graze on corn lily ingest cyclopamine (shown) and veratramine, two of a sub-family of<unk> s where the C- and D-rings are contracted and expanded respectively via a biosynthetic migration of the original C-13 atom. Ingestion of these C-nor-D-homosteroids results in birth defects in lambs: cyclopia from cyclopamine and leg deformity from veratramine. A further C-nor-D-homosteroid (nakiterpiosin) is excreted by Okinawan cyanobacteriosponges. e.g., Terpios hoshinota, leading to coral mortality from black coral disease. Nakiterpiosin-type<unk> s are active against the signaling pathway involving the smoothened and hedgehog proteins, a pathway which is hyperactive in a number of cancers.
Steroid
Antibiotic
Antimicrobial
Steris
Analgesic
Antipyretic
Broad-spectrum antibiotic
Antiparasitic