9 May 2005
Obesity Hormone Linked To Penis Function
by George Atkinson

United Kingdom researchers from the University of Warwick have found that a hormone normally associated with obesity is also very active in the male genitals, where it plays a key role in male fertility and appears to influence the erection response in male sexual arousal. The research has focused on the protein orexin, which stimulates the human adrenal gland to produce cortisol which in turn can cause obesity. But now, for the first time, the researchers have found clear evidence that orexin activity can be found in several areas of the male genitals where it appears to have a more positive affect.

Orexin, named after the Greek word for appetite, seems to act on a number of areas within the testes and penis, including:

• The testicular cells responsible for making testosterone, the primary male sex hormone, and in tubules that are responsible for producing sperm.
• An area called the epididymis, implicating orexins in events that include the transport and storage of sperm cells.
• The penis, which implicates orexin in the control of penile function including the maintenance of penile erection.