Endocrine Disorders & Endocrine Surgery is the largest site on the web for thyroid, parathyroid, adrenal, and pancreatic disorders. The anatomy and function of each endocrine gland is described along with various surgical procedures and disorders.

http://www.endocrineweb.com/

Melatonin: Separating the Hype from the Hormone is an article by the Mayo Clinic's Health Oasis that refutes many of the current beneficial claims associated with taking this hormone.

http://www.mayohealth.org/mayo/9708/htm/melaton.htm

Athletes sometimes take powerful anabolic steroids to increase muscle mass and athletic performance. Few people realize that for women, the physical masculinizing effects of these hormones are irreversible. Other side effects of anabolic steroids can range from serious to life threatening. Read more about anabolic steroids at this site by Drug-Free Resource Net - Partnership for a Drug-Free America.

http://www.drugfreeamerica.org/steroids.html