Sex steroid hormone metabolism and prostate cancer

IUPAC-approved ring lettering and atom numbering. A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids can also be more radically modified, such as by changes to the ring structure, for example, cutting one of the rings. Cutting Ring B produces secosteroids one of which is vitamin D3.

Lanosterol, the biosynthetic precursor to animal steroids. This structural lipid and key steroid biosynthetic precursor. This section needs attention from an expert in Pharmacology. In eukaryotes, steroids are found in fungi, animals, and plants. Fungal steroids include the ergosterols, which are involved in maintaining the integrity of the fungal cellular membrane. Sex hormones, which influence sex differences and support reproduction.

These include androgens, estrogens, and progestogens. Anabolic steroids, natural and synthetic, which interact with androgen receptors to increase muscle and bone synthesis. In popular use, the term “steroids” often refers to anabolic steroids. This section needs expansion with: a more full discussion of this most prominent structural type. You can help by adding to it. Steroids can be classified based on their chemical composition. One example of how MeSH performs this classification is available at the Wikipedia MeSH catalog.

17-carbon tetracyclic hydrocarbon molecule with no alkyl sidechains. Major secosteroid subclasses are defined by the steroid carbon atoms where this scission has taken place. Combinations of these ring alterations are known in nature. Steroids such as cholesterol decrease membrane fluidity. Steroids play critical roles in a number of disorders, including malignancies like prostate cancer, where steroid production inside and outside the tumour promotes cancer cell aggressiveness.

Steroid biosynthesis is an anabolic pathway which produces steroids from simple precursors. Human steroidogenesis, with the major classes of steroid hormones, individual steroids and enzymatic pathways. Changes in molecular structure from a precursor are highlighted in white. Steroidogenesis is the biological process by which steroids are generated from cholesterol and changed into other steroids. The pathways of steroidogenesis differ among species.

Progestogens are the precursors of all other human steroids, and all human tissues which produce steroids must first convert cholesterol to pregnenolone. This conversion is the rate-limiting step of steroid synthesis, which occurs inside the mitochondrion of the respective tissue. Cortisol, corticosterone, aldosterone, and testosterone are produced in the adrenal cortex. Stromal cells have been shown to produce steroids in response to signaling produced by androgen-starved prostate cancer cells.

In plants and bacteria, the non-mevalonate pathway uses pyruvate and glyceraldehyde 3-phosphate as substrates. During diseases pathways otherwise not significant in healthy humans can become utilized. Steroids are primarily oxidized by cytochrome P450 oxidase enzymes, such as CYP3A4. These reactions introduce oxygen into the steroid ring, allowing the cholesterol to be broken up by other enzymes into bile acids. Methods of analysis overlap both of the above areas, emphasizing analytical methods to determining if a steroid is present in a mixture and determining its quantity. Also available online at “The Nomenclature of Steroids”.

London, GBR: Queen Mary University of London. International Union Of Biochemistry And Molecular Biology. The New England Journal of Medicine. Bhetariya PJ, Sharma N, Singh P, Tripathi P, Upadhyay SK, Gautam P.