Morphine can help reduce the hormone testosterone in the brain and plasma, a study said.

Researchers found that the level of testosterone in the brain and plasma was reduced considerably after just a single injection of morphine on male rats. Morphine is used to treat persistent pain.

The study published in Molecular Pain showed that opioids had "long lasting genomic effects in body areas which contribute to strong central and peripheral testosterone levels" including the brain, the liver and the testis.

The study is led by Anna Maria Aloisi, M.D., of the Department of Physiology – Section of Neuroscience and Applied Physiology at the University of Siena, Italy, Sbarro Institute for Cancer Research and Molecular Medicine at Temple University in Philadelphia, University of Siena, and the Human Health Foundation in Spoleto, Italy.

Aromatase, an enzyme that is responsible for one of the key steps in the biosynthesis of strogen increased with the Morphine shot. The study could throw light on how the hormones function in cognitive functions as well as in mood, motor control and in many other functions, such as bone structure remodeling."

Our lab became interested in gonadal hormones several years ago when it became clear that there were many differences in pain syndromes between the sexes," says Dr. Aloisi. "In looking at differences, it was immediately apparent that these changes were introduced by different treatments, opioids in particular."

"The research findings are very relevant to the management of patients with chronic pain," said Marco Pappagallo, M.D., professor and director of pain research and development, Department of Anesthesiology, Mount Sinai School of Medicine, New York, NY.

"Today, primary care physicians, pain specialists, and a variety of health care professionals are asked not only to treat pain but how to manage side effects of drugs and to strive for the best possible comprehensive care and wellness of patients who experience chronic pain.

Opioid induced hypogonadism can cause health complications to which patients with pain can be overly susceptible, including chronic fatigue, loss of stamina, emotional and sexual disturbances, and as well painful skeletal and muscular complications."

"Until a few years ago this condition was completely unrecognized by physicians although some reports clearly showed it in many kinds of patients," notes Dr. Aloisi. "Today there remains some ignorance on this condition but gonadal hormones are more commonly cited as responsible for much chronic degenerative pathology."