MadSci Network: General Biology
Query:

Re: CAN YOU REVERSE AGING PROCESS 10-20 YEARS WITH GROWTH HORMONE?

Date: Mon May 3 09:48:20 1999
Posted By: James Goss, Post-doc/Fellow, Neurology, University of Pittsburgh
Area of science: General Biology
ID: 922503943.Gb
Message:

   I’m sorry I haven’t answered your question Matthew but I have been on 
vacation and completely forgot to submit my answer before I left.  You ask 
an interesting question concerning the use of growth hormone (also called 
somatotropin) to reverse aging.  Growth hormone (GH) is one of several 
hormones released from the pituitary.  The pituitary is a thumb-sized organ 
which is tethered to the brain by a narrow strand of tissue.  It releases 
at least 8 different hormones into the blood stream, many of which control 
other endocrine glands (an endocrine gland is any organ which releases 
hormones into the bloodstream.  A hormone is a chemical substance which is 
released by one cell, travels through the body, and affects the functioning 
of a separate distant cell) and therefore it is often referred to as the 
"master gland".  GH acts directly on the long bones of the body, and the 
joints and muscles, causing them to grow during development.  The absence 
of GH causes dwarfism, while too much GH causes giantism.  Indeed, long 
term elevations in GH in adults cause a disorder known as acromegaly, in 
which the bones of the hands and face become thickened and distorted 
because the long bones are unable to grow.  
   The idea of using GH to combat or reverse aging is due to two main 
observations.  First, there is a decline in the amount of GH released by 
the pituitary during aging.  Second, aging is often associated with 
osteoporosis (loss of bone mass), arthritis (inflammation of the joints), 
and loss of lean muscle mass.  It has been reasoned that these changes in 
bone, joints, and muscle with age may be due to the loss of GH, and 
further, that replacing this GH in the elderly may reverse these effects.  
In addition, evidence of the ability of GH to build muscle mass in adults 
was seen in athletes how misused GH in order to enhance their strength and 
stamina.  A couple of well publicized studies in the early 1990’s claimed 
that administration of GH to older men slowed the aging process.  In these 
studies, the men who received GH had lower fat content, increased muscle 
mass, and increased bone mineral density.  However, GH treatment also 
resulted in increased blood pressure and blood sugar.  Subsequent 
controlled clinical studies in humans and studies using laboratory animals 
have had conflicting results.  Today, research concerning GH and aging is 
going strong, but few scientists believe that GH therapy will have a major 
impact on aging.  It is more likely that GH replacement therapy may be used 
in conjuncture with other life-style changes (i.e. change in diet, 
increased exercise, etc) to help reduce bone and muscle loss in the 
elderly.  I would have to say that GH therapy will not reverse the aging 
process by 10 to 20 years (it certainly will not increase lifespan), but 
that low dose therapy might have some beneficial effects.  I say low dose 
therapy because it should be pointed out that too much GH is probably worse 
than too little GH.  Mice which have been genetically altered to make too 
much GH die sooner than normal mice, and show signs of accelerated aging.  
Also, Robert Wadlow, the worlds tallest recorded man, who was 8’11" died 
at the age of 22 from a minor injury because his immune system was altered 
due to his increased GH.
   If you are interested in reversing the aging process, the only proven 
method to increase lifespan in laboratory animals is dietary restriction.  
Significantly reducing the normal food intake of rats and mice (I cannot 
remember the actual amount but I think it is 40% - 60%) will increase their 
lifespan (again I think by 20% - 30%).  There is some evidence that this 
may hold true for laboratory primates also.  I, for one, however, do not 
practice this.




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