IGF-1 and Growth Hormone - Good News - Bad NewsA news report this week describes research on the effects of growth hormone and IGF-1 that might seem alarming at first glance. Researchers developed a strain of dwarf rats that were born deficient in both growth hormone and IGF-1. Since these hormones usually increase during adolescence, the scientists gave some of the rats hormone treatments between the ages of 4 and 14 weeks, and compared them to rats that had lower hormones throughout their lives. All the rats were allowed to live out their normal lifespan and died of natural causes. Fatal cancerous tumors killed 57% of the of the rats receiving hormone supplementation, and only 31% of the rats with lifelong deficiencies. The hormone deficient rats lived on average 14.6% longer than the treated ones. On the other hand, the hormone deficient rats performed poorly on tests of memory or learning. They also showed increased cartilage degeneration. The researchers concluded that cancer risk as well as other age-related pathologies could be substantially decreased in these animals by inducing a modest deficiency of growth hormone and IGF-1 early in life. However, there is a tradeoff and deficiency of growth hormone and IGF-1 may impair learning and memory and accelerate some degenerative diseases. Note however that this study does not correspond to the use of supplemental hormones by humans to improve their health in old-age. All of the rats had relatively low hormone levels throughout their adult lives, the added hormones were only given during adolescence. That the cancerous growths occured so long after the hormone treatment only shows how little we understand the causes of cancer. This study stands as a stark warning to those young atheletes who hope to improve their performance by using hormone supplementation, but has little of relevance to older adults seeking to improve their health after the natural decrease in hormone levels has begun. |
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