"The effects of declining androgen secretion on mood regulation" and the possible benefits of androgen replacement "are largely undetermined," Dr. Peter J. Schmidt and colleagues from the National Institutes of Health (news - web sites) in Bethesda, Maryland, write in the Archives of General Psychiatry.

The researchers examined the effects of suppressing testosterone secretion on mood in 31 healthy men with no history of psychiatric illness or anabolic steroid abuse, which can affect normal testosterone production.

The men were given injections of Lupron every 4 weeks for three months to drastically reduce testosterone levels. After the first 4 weeks, the men were randomly assigned to receive, in addition to Lupron, testosterone or placebo injections, every 2 weeks for one month. They were then switched to the other injection for the final month of the study.

Without the testosterone replacement, men reported significant increases in hot flush severity and significant decreases in sexual interest and the feeling of being "emotionally charged."

"Men with high baseline sexual interest had a significant decrease in sexual interest during Lupron plus placebo, and levels of sexual interest were restored to baseline levels during Lupron plus testosterone," Schmidt's team reports.

However, no significant differences in sadness, anxiety, irritability, or decreased energy were seen between the Lupron plus placebo and the Lupron plus testosterone periods.

"Overall, our data suggest that acute androgen withdrawal, while associated with decreased libido and hot flushes, is not sufficient to uniformly alter mood in healthy young adult men," the researchers conclude.