Growth hormone is naturally produced in the body and in turn stimulates the release of another hormone called insulin-like growth factor-1 (IGF-1). Studies on mice have suggested that IGF-1 might reduce beta-amyloid plaques (which are one of the main symptoms of Alzheimer's disease) and scientists have been wondering whether boosting the levels of IGF-1 in the human body might help to combat Alzheimer's. Researchers at Merck Research Laboratories in the U.S. looked into a compound called MK-677 which stimulates the release of natural growth hormone from the pituitary gland, which in turn stimulates the release of IGF-1 in other parts of the body. The researchers divided 416 people with mild-to-moderate Alzheimer's disease into two groups, one taking MK-677 and the other taking a placebo. They found that although MK-677 did boost people's levels of IGF-1 it did nothing to slow the development of the amyloid plaques.
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