It should not be a surprise to see suppression of growth hormone in mammals result in extended healthy life spans. After all, the present record holder for the Mprize for mouse longevity involved gene engineering of a growth hormone deficient breed. Here researchers demonstrate benefits in a mouse breed used for Alzheimer's research, as it develops accelerated degeneration of the brain: "people sometimes take growth hormone, believing it will be the fountain of youth. ... Many older people have been taking growth hormone to rejuvenate themselves. These results strongly suggest that growth hormone, when given to middle aged and older people, may be hazardous. ... The scientists studied the compound MZ-5-156, a 'growth hormone-releasing hormone (GHRH) antagonist.' They conducted their research in the SAMP8 mouse model, a strain engineered for studies of the aging process. Overall, the researchers found that MZ-5-156 had positive effects on oxidative stress in the brain, improving cognition, telomerase activity (the actions of an enzyme which protects DNA material) and life span, while decreasing tumor activity. MZ-5-156, like many GHRH antagonists, inhibited several human cancers, including prostate, breast, brain and lung cancers. It also had positive effects on learning, and is linked to improvements in short-term memory. The antioxidant actions led to less oxidative stress, reversing cognitive impairment in the aging mouse."