Another way to prolong life: to suppress the growth hormone activator
Growth Hormone Blocking Protein Prolongs Life
Alla Solodova, Infox.ruScientists have found a protein that activates telomerase, an enzyme that allows cells not to age.
The compound is synthesized in the brain and interferes with the work of growth hormone.
Aging is a gradual complex disruption of cellular and molecular processes and the loss of important vital functions, in particular, the ability to reproduce and regenerate. Aging animals become more vulnerable to environmental factors and quickly die without experiencing all the "charms" of age-related diseases. A person feels aging in all parts of the body – from hearing loss, baldness, loss of physical activity and endurance to neurodegenerative, cardiovascular and oncological diseases.
Catalysts of aging
The rate of aging depends on numerous, not always clear biochemical reactions. (For the latest data on changes in mitochondrial processes that prematurely age lovers of a good meal, see the article "Low–calorie diet: sirtuins against aging in general and deafness in particular" - VM). And in an experiment with deaf mice, scientists from the USA and Japan explained how dietary restrictions smooth out oxidative stress, prolonging life.
William A.Banks from the University of Washington and his colleagues studied the dependence of aging not on width, but on height. They investigated the influence of the role of growth hormone, the lack or excess of which spoils health according to senile "scenarios".
ControversiesGrowth hormone (somatropin, STH) is the main hormone that stimulates linear growth.
STH promotes the growth of bones in length, the development of internal organs and muscle tissue. It is believed that in an adult (already grown) person, the hormone interferes with the aging process.
STH is synthesized throughout life, but its amount decreases over the years. And in patients with excessive amounts of growth hormone (acromegaly), the skin and bones change according to the "scenario", reverse aging. That is, the skin and bones of people with an excessive amount of STH do not thin out with age (do not age). At the same time, additional injections of the hormone do not prolong a person's life and are even associated with increased mortality of patients. Groups of independent researchers came to such conclusions after analyzing databases of clinical trials. In addition, patients with acromegaly more often and earlier begin to suffer from cardiovascular and oncological diseases. It turns out that STH seems to prevent aging and at the same time supports the premature appearance of age-related diseases.
In vivo experiments also contradict the "rejuvenating" properties of the hormone. Thus, mice with a deficiency of STH or with a reduced sensitivity to this hormone live longer than their healthy relatives. Organs (including the brain) of rodents with an excessive amount of STH wear out earlier than expected.
Rejuvenating anti-growthResearchers from the University of Washington (University of Washington), the University of Miami (University of Miami) and the University of Missouri (Missouri University of Science and Technology) studied how growth hormone affects the molecular and cellular mechanisms involved in the aging process.
For the experiment, the scientists used mice with a short lifespan (about sixteen months), prone to age-related accumulation of amyloid protein and beta-amyloid precursors. That is, the very compounds that disrupt the work of internal organs and cause senile dementia (Alzheimer's disease). As an "elixir of youth and health", the experimenters used proteins that block the hormone that stimulates the synthesis of STH.
In the first experiment, William Banks and his colleagues began treating "short-lived" mice at the age of ten months. By this time, their body has already formed and begins to age gradually. It turned out that daily injections of the STH suppressor prolong the life of mice. So, animals from the control group died on average 26 weeks after the start of the experiment (before they reached the age of 16 months). Rodents from the experimental group lived eight weeks longer.
In the next experiment, the scientists found out that 1.7% of the animals from the test group got cancer. In animals from the control group, malignant neoplasms appeared in 10% of cases. William Banks notes that the results obtained do not contradict the literature data, which reliably recorded a decrease in the incidence of cancer in animals with STH deficiency. Moreover, in medical and biological studies, suppressants of STH synthesis also slowed down the growth of tumors of the prostate, breast, brain, intestines and lungs.
In cognitive tests, the test mice also outperformed the animals from the control group. However, the physical strength and endurance of both groups did not differ. But the "elixir of youth" strengthened the resistance of animals to the action of free radicals and somewhat changed the biochemistry of blood. Most of all, scientists were surprised to learn that the suppressor of STH synthesis increases the activity of telomerase – the very enzyme that grows chromosomes "tails" and in this way promotes aging and the accumulation of mutations. Moreover, in some parts of the body (for example, the liver and aorta), telomerase activity increased four to five times.
"The results of a comprehensive study suggest that STH activator blockers rejuvenate the body at the cellular-molecular level - prevent oxidative stress and activate telomerase," the researchers write in the article Effects of a growth hormone–releasing hormone antagonist on telomerase activity, oxidative stress, longevity, and aging in mice, published in PNAS.