Pace of Life and and the Longevity Resulting From Growth Hormone Deficiency in Mice

The longest lived mice to date are those in which growth hormone signaling is disrupted, such as via growth hormone receptor knockout. While larger species tend to be longer lived, within a given mammalian species greater body size (and thus greater growth hormone activity) appears to reduce life expectancy. The effect is much more pronounced in short-lived species such as mice than in long-lived species such as our own, however. An inherited loss of function mutation in growth hormone receptor in humans produces Laron syndrome in a small population, but these individuals do not appear to live any longer than the rest of us. Mice with genetic growth hormone (GH) deficiency or GH resistance live much longer than their normal siblings maintained under identical conditions with unlimited access to food. Extended longevity of these mutants is associated with extension of their healthspan (period of life free of disability and disease) and with delayed and/or slower aging. Importantly, GH and GH-related traits have been linked to the regulation of aging and longevity also in mice that have not been genetically altered and in other mammalian species including humans. Available evidence indicates that the impact of suppressed GH signaling on aging is mediated by multiple interacting mechanisms and involves trade-offs among growth, reproduction, and longevity. Life history traits of long-lived GH-related mutants include slow postnatal growth, delayed sexual maturation...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs