Insulin sensitivity decreased among those taking MK-677, while their blood sugar increased. The therapy did not have any observable effect on the muscularity of the thigh area -- a key source of mobility strength -- nor did it have any impact on overall muscle strength or activity function, the team noted.
"But the patients we studied were healthy to begin with," Thorner stressed. "So, we believe that we now need a longer-term study with possibly more frail individuals, to see if we can demonstrate any possible change or improvement in function as a result of the therapy."
Thorner noted that a person's growth hormone levels are highest during mid-puberty, but have dropped by about half by the time men and women turn 30. The decline continues with age, with levels diminishing at a rate of about 50 percent every 7 years.
Dr. Todd Schlifstein, an assistant professor of rehabilitation medicine at the New York University School of Medicine in New York City, called the study "very interesting" but agreed that more research is needed.
"I think it certainly enlightens an area where there certainly seems like there is a potential for a benefit for elderly patients," he said. "But now it needs to be looked at further in a functionality type of way, to see how an increase in appetite, body energy, and lean muscle mass actually translates into how a patient actually walks, for example, and how it impacts on their over well-being, which is much harder to test. But that's the next step."
There's more on maintaining muscle mass as you age at the U.S. National Institute on Aging.
SOURCES: Michael O. Thorne
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