"Growth hormone-releasing hormone doesn't target one specific area in the body and brain," said study lead author Laura Baker, an associate professor of psychiatry and behavioral science at the University of Washington School of Medicine, in Seattle. "It stimulates a whole cascade of hormones in the body and brain; it stimulates normal function of a system that was working at a younger age so that cells can do what they were programmed to do at birth."

Results of the study are published in the Aug. 6 issue of the Archives of Neurology.

As levels of growth hormone-releasing hormone (GHRH) decrease with age, so too do other hormones stimulated by GHRH, such as growth hormone and insulin-like growth factor 1. All of these hormones are believed to play a role in brain health, and decreasing levels of these hormones are suspected to play a role in the development of Alzheimer's disease.

In a previous study, Baker and her colleagues demonstrated that treatment with GHRH provided a short-term boost in memory and concentration for healthy adults. In the current study, they wanted to see if GHRH could help restore some function in people who were showing signs of a condition known as mild cognitive impairment. People with this condition don't yet have Alzheimer's disease, but they do have problems with memory and focus, and they're at higher risk of developing Alzheimer's disease, according to the Alzheimer's Foundation.