A “male hormone” — a sex hormone produced by the testes that encourages the development of male sexual characteristics, stimulates the activity of the male secondary sex characteristics, and prevents changes in them following castration. Chemically, testosterone is 17-beta-hydroxy-4-androstene-3-one.
Testosterone is the most potent of the naturally occurring androgens. The androgens cause the development of male sex characteristics, such as a deep voice and a beard; they also strengthen muscle tone and bone mass.
High levels of testosterone appear to promote good health in men, for example, lowering the risks of high blood pressure and heart attack. High testosterone levels also correlate with risky behavior, however, including increased aggressiveness and smoking, which may cancel out these health benefits.
Testosterone may be given to treat medical conditions, including female (but not male) breast cancer, hypogonadism (low gonadal function) in the male, cryptorchism (nondescent of the testis into the scrotum), and menorrhagia (irregular periods).
- Testosterone replacement therapy
The practice of giving testosterone to treat conditions in which the testes do not produce enough testosterone. This may be due to absence, injury, or disease. Testosterone is available in oral, IV, and patch forms. As with estrogen replacement therapy for women, dosing must be carefully calibrated to gain the greatest benefits without unwanted side-effects.
An often fatal infectious disease that is caused by the bacterium Clostridium tetani, which usually enters the body through a puncture, a cut, or an open wound. Tetanus leads to profound painful spasms of muscles, including ‘locking’ of the jaw so that the mouth cannot open, and death. The C. tetani bacteria releases a toxin […]
A condition that is due usually to low blood calcium (hypocalcemia) and is characterized by spasms of the hands and feet, cramps, spasm of the voice box (larynx), and overactive neurological reflexes. Tetany is generally considered to result from very low calcium levels in the blood. However, tetany can also result from reduction in the […]
A family of broad-spectrum antibiotics effective against a remarkably wide variety of organisms. Bacteria susceptible to tetracycline include H. flu (Haemophilus influenzae), strep (Streptococcus pneumoniae), Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, and Neisseria gonorrhoeae (the cause of gonorrhea). Tetracycline is also used to treat nongonococcal urethritis (due to Ureaplasma), Rocky mountain spotted fever, typhus, chancroid, […]
A substance that is a possible carcinogen (cancer-causing agent) used in the production of polymers such as polytetrafluoroethylene. The US government in 2000 classified tetrafluoroethylene as “reasonably anticipated to be a human carcinogen.” In laboratory animal studies of tetrafluoroethylene, cancer was observed in multiple organs of multiple species following long-term inhalation exposures.