The early steps in the biosynthesis of steroids of both plants and animals are the same, except that in plants lanosterol is replaced by the related compound cycloartenol, which contains a three-membered ring (C9, C10, C19) in lieu of the nuclear double bond of lanosterol. The side chains of the phytosterols, such as stigmasterol, and of the sterol ergosterol of yeasts and other fungi contain extra carbon atoms that are incorporated in reactions involving S -adenosylmethionine, which donates methyl groups in numerous biological processes. Although most plant tissues contain only traces of cholesterol, this sterol is the biogenetic precursor of such important plant steroids as the sapogenins , glycosides , and alkaloids . Because pregnane derivatives are intermediates in some of these transformations, plants and animals appear to have important features of steroid metabolism in common.
Awareness and educational efforts are working to help prevent anabolic steroid abuse in schools and communities. The Adolescents Training and Learning to Avoid Steroids (ATLAS) and the Athletes Targeting Healthy Exercise and Nutrition Alternatives (ATHENA) programs, funded by the NIDA, and supported by the Oregon Health & Science University programs is teaching athletes that they do not need steroids to build powerful muscles and improve athletic performance. These programs provide weight-training and nutrition alternatives, increase healthy behaviors, less likelihood to try steroids, and less likelihood to engage in other dangerous behaviors such as drinking and driving, use of marijuana and alcohol , and and improved body image. Bother Congress and the Substance Abuse and Mental Health Services Administration endorsed these model prevention programs. 4