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What is a hormone? A hormone is one of the many chemical
messengers of the body. Hormones are comprised of proteins that form
peptide chains and direct the functions of our body. One of the most
vital of these chemical messengers is Human Growth Hormone.
We here at Bio-Identical Hormone Replacement Therapy
MD, the Conscious Evolution Medical Institute, want to do everything
we can to help you make an informed decision about Hormone Replacement
Therapy. Therefore, we have compiled this information about the history,
benefits, pros, and cons of growth hormone imbalance treatment.
GH (Growth Hormone), also known as STH (somatotropin)
is a hormonal protein that stirs growth and also the reproduction of
cells in people and many animals. It's a lone chain of one hundred ninety
one amino type acids that makes up a hormone of the polypeptide variety.
It is manufactured, secreted, and stored by somatotrophic cells inside
the lateral wings of the anterior of the pituitary gland.
The following information about the physiology of
Growth Hormone also reviews briefly diseases caused by a deficiency
of Human Growth Hormone as well as excessive Growth Hormone (gigantism
and pituitary acromegaly). It also discusses treatment that features
Human Growth Hormone. To learn more about a commonly used growth hormone
that is often given to cattle, look up bovine somatotropin.
Terms
Recombinant HGH Human Growth Hormone is called somatotropin
as well (In Britain: Somatotrophin)
HGH is an acronym for Human Growth Hormone. This
hormone, HGH, is released from or extracted in a measured fashion from
the pituitary gland of human beings.
In the 1980s, Human Growth Hormone of biosynthetic
form replaced Human Growth Hormone that was derived from the pituitary
in bio hormone replacement therapy used in the United States and other
locations. Previously, Human Growth Hormone was gathered from processed
pituitary glands. Biosynthetic HGH, also referred to as Recombinant
Human Growth Hormone, is known as Somatropin and the abbreviation rhGH
is used.
From the middle of the 1980s, the HGH abbreviation
started to carry connotations that were paradoxical. It now quite rarely
is used in reference to Human Growth Hormone for the purposes that are
indicated.
Gene and Structure of an HGH molecule
The HGH genes are located at region q22-24 of the
17thchromosome (GH1). They happen to be related closely to hCS (human
chorionic somatomammotropin, known also as lactogen of the placenta)
genes. Human Growth Hormone, PRL (prolactin) and hCS (chorionix somatomammotropin)
make of a group of similar hormones that promote growth and activity
that is lactogenic.
The predominant isoform that comprises Human Growth
Hormone is a one hundred ninety one amino acid protein chain that has
a molecular weight that is twenty two thousand daltons. The configuration
has four helixes that are needed for interaction that is functional
with the Growth Hormone Receptor. Growth Hormone is believed to be evolutionarily
and is structurally similar to chorionic somatomammotropin and prolactin.
Even though there are real similarities within the structure that correlate
Human Growth Hormone with that of other species, only the HGH from primates
and humans has a significant effect on people.
Secretion of Growth Hormone
Many molecular configurations of growth hormone move
through the body. A large portion of the HGH circulating through the
body is attached to a particular protein called growth hormone binding
protein, or GHBP. The protein is manufactured by the Growth Hormone
receptor.
Hormone Regulation
The hypothalamus releases peptides from the neurosecretory
nuclei and those peptides enter the veins around the pituitary gland.
These peptides are significant in that they stimulate the secretion
of Growth Hormone by the body's somatotropes. But, even though a balance
of the inhibiting and stimulating peptides controls the release of growth
hormone, the balance is also affected by numerous physiological inhibitors
and stimulators of Growth Hormone Secretion.
Stimulators of Growth Hormone Secretion include:
GHRH (Growth Hormone Releasing Hormone) that originates
from the arcuate nucleus.
Sleep
Ghrelin (hunger-stimulating hormone)
Exercise
Dietary protein estradiol
Low levels of blood sugar (hypoglycemia)
Arginine[2] (decreases blood pressure and enhances
injury recovery)
Growth Hormone secretion inhibitors include:
Somatostatin that originates in the periventricular
nucleus
Glucocorticoids (carbohydrates of a dietary variety)
Levels of Insulin-Like Growth Factor-1 and Growth
Hormone circulation concentration (the body reacts negatively to this
feedback)
Secretion of Growth Hormones is stimulated in non-endogenous
therapies as well. There are a significant number of exogenic compounds
known as xenobiotics that have been proven to stimulate and inhibit
the function and secretion of Growth Hormones. This highlights the theory
that the axis of Insulin-Like Growth Factor-1 and Growth Hormone is
proving to be a vital target for particular chemicals that disrupt the
endocrine system (referred to as endocrine disruptors).
Patterns of Secretion
The majority of physiologically vital secretion happens
during a number of large peaks or pulses of growth hormone release every
day. The concentration of growth hormone in blood plasma during one
of these peaks can range from five to thirty five ng/mL or even more.
These peaks usually last a duration of ten to thirty minutes before
they return to normal levels. The most predictable and largest of the
growth hormone peaks happens around an hour after one goes to sleep.
Besides this particular time, there is a wide variety of Growth Hormone
release patterns from person to person and even from day to day within
a particular person. Between peaks, base levels of growth hormone remain
low, most often less than three ng/mL for most of the night and day.
Also, the pattern and amount of growth hormone that
is secreted changes over the course of one's life. Base levels of Growth Hormone
are at their highest at the beginning of childhood. The frequency and
amplitude of peaks is at its greatest during the growth spurt of puberty.
Healthy adolescents and children average around eight peaks every 24
hours. Adults usually have around five peaks. The amplitude and frequency
of peaks as well as base levels of Growth Hormone drop as one becomes older.
Growth Hormone Functions
The effect that Growth Hormone has on human tissue can
most accurately be termed anabolic (meaning having a stimulative effect).
Similarly to the majority of other hormonal proteins, growth hormone
functions through interaction with a particular receptor that is located
on the outer surface of the cell.
Increases Height
The stimulation of growth in height during childhood
is the most well known effect of growth hormone action. It appears to
be spurred by a minimum of 2 mechanisms.
Growth hormone stimulates the multiplication and
division of the chondrocytes located in the cartilage. Chondrocytes
are the main cells in the epiphyses (growing ends) of the long bones
of a child's body (digits, arms, legs).
Growth hormone also encourages manufacture of IGF-1
(insulin-like growth factor 1, known previously as somatomedin C). IGF-1
is a hormone that is similar to proinsulin. Creation of IGF-1 occurs
primarily in the liver, and stimulation through Growth Hormone is necessary
for this vital process to occur correctly.
IGF-1 also has stimulative growth effects on various
types of tissue. IGF-1 is manufactured to a lesser extent inside the
tissues that are targeted, which makes Insulin-Like Growth Factor-1 seemingly
an endocrine hormone as well as a paracrine/autocrine hormone. Also,
IGF-1 has stimulative effects upon chondrocyte and osteoblast activity,
leading to a promotion of the healthy growth of one's bones.
Other Functions of Growth Hormone
Though Growth Hormone's most well known effect is the
stimulation of height growth, it also stimulates a variety of other
metabolic processes.
Below is a list of some of these processes:
- Increase in the retention of calcium, which increases
bone mineralization and strengthens the bones as well
- Increase in muscle mass due to the genesis of new
muscle cells (also known as hyperplasia, which differs significantly
from hypertrophy)
- Promotion of lypolysis. This results in a loss of body fat, medically known
as adipose tissue.
- Increase in the synthesis of proteins which stimulates
growth and maintenance of every organ of the body, in exclusion of the
brain
- Role in homeostasis of fuel production. Growth Hormone
reduces the liver's intake of glucose, which opposes the hormone of
insulin.
- Promotion of gluconeogenesis in the liver
- Contribution to the proper function and maintenance
of the islets of the pancreas
- Stimulant of the immune system
Diseases that are a result of an excess of growth hormone
(acromegaly and pituitary gigantism)
The disease which is most common that results in
an excess of growth hormone is a pituitary gland tumor comprised of somatotroph
cells that normally reside in the anterior of the pituitary gland. These
somatotrophic adenomas are not cancer causing and they grow very slowly,
producing a greater and greater amount of growth hormone as they develop.
For many years, the main medical issue that arises from a somatotrophic
adenoma is an excess of growth hormone. After many years, the adenoma
can become so large that it begins to cause headaches and impair vision
due to the pressure it creates upon the optical nerve. It can also create
a deficiency of other hormones by displacing them on the pituitary gland.
Prolonged excess of growth hormone can lead to a
thickening of the bones of the toes, fingers, and jaw. The jaw heaviness
and digit thickness that occurs as a result is known as acromegaly. Problems
that accompany acromegaly often include pressure upon the nerves (carpal
tunnel among other conditions), weakness of the muscles, a reduction
of sexual ability, and even possibly resistance to insulin, which can
result in a rare kind of type-2 diabetes.
Tumors that secrete growth hormone are most often
discovered during a patient's 50s. It is very uncommon for this type
of tumor to develop during childhood or adolescence, but if it does
develop, it can lead to an excess of growth hormone that can lead to
excessive growth commonly called pituitary gigantism. Growth hormone-producing
tumors are usually treated by means of surgical removal. In unique cases,
focused blasts of radiation may be used. In other cases, a Growth Hormone
antagonist like octreotide or bromocriptine may be administered to block
the function of growth hormone or cause the tumor to shrink.
Deficiency of Growth Hormone (GHD)
A deficiency of growth hormone can produce very different
issues dependent upon the age at which the deficiency occurs. In young
children, an inhibition of growth leading to short stature and size
is the most common manifestation of Growth Hormone Deficiency. For adults,
however, effects that are caused by Growth Hormone deficiency are much
more subtle. These effects can include weakness, lack of energy, reduction
in bone mass in addition to a higher risk of cardiovascular complications.
There are numerous causes of Growth Hormone deficiency.
These include genetic mutations, genetic defects of the pituitary and/or
the hypothalamus, and also damage that occurs to the pituitary gland
from disease, surgery, or injury.
A proper diagnosis of Growth Hormone Deficiency is
a multi-step diagnostic procedure which usually culminates in growth hormone
stimulation tests. In these tests, various stimuli are administered
in an effort to spur the pituitary gland into releasing a pulse of Growth
Hormone.
A deficiency in Growth Hormone is treated through bio
identical hormones therapy. All of the Growth Hormone that is currently
used is of a biosynthetic variety created through technology derived
from recombinant DNA.
Because Growth Hormone is a very large protein, it
has to be administered by injection into subcutaneous tissue to reach
the blood stream. Injections used to be administered into muscle mass
until 1985, when manufacture of synthetic Growth Hormone began. If an
individual has been long-suffering from the effects of Growth Hormone
deficiency, treatment benefits are quite often gratifying and dramatic.
Side effects are rare, as well. When Growth Hormone is used properly
in children who have a deficiency, the end result is a more normal and
average height in adulthood.
Growth Hormone Replacement Therapy is used as a treatment
for adults that struggle with a Growth Hormone deficiency of adult-onset
(which is usually caused by the development of a tumor on the pituitary
gland) or childhood-onset (upon completion of the growth phase). In
these individuals, the benefits often include a reduction in body fat,
an increase in lean muscle, stronger bones, improved cholesterol levels,
fewer risk factors for cardiovascular complications, and an overall
improvement in mental well being.
Advantages of Hormone Replacement Therapy
Other uses for Growth Hormone and other indications of treatment
A number of other ailments other than Growth Hormone
deficiency can lead to lackluster growth; however, the benefits of growth
and height gain are very often poorer when not treated for Growth Hormone
Deficiency as well.
Other examples of reduced stature that feature treatment
regimens involving Growth Hormone include:
Chronic Renal Failure
Turner syndrome
Prader-Willi syndrome
In-utero growth complications
Severely small stature with no discernible cause
In conditions such as these, larger, pharmacological
doses of Growth Hormone are needed to induce growth. The amount of Growth
Hormone administered to the body by an HRT doctor in these instances
is much higher than normal physiological levels. Luckily, treatment
with these pharmacological doses rarely result in unwanted hormone side
effects. Also, the Growth HRT side effects show little variation relative
to the condition treated.
Often, Growth Hormone is utilized to attain benefits
other than an increase in height. Growth Hormone Replacement Therapy
leads to an increase in muscle strength and a modest reduction in body
fat for those who suffer from Prader-Willi syndrome. In those children
who suffer from this condition, these two benefits are significantly
more vital than simply growing in height. Growth Hormone has also proven
to be useful to ward off the muscle atrophy and wasting caused by AIDS.
Growth Hormone also can be administered to individuals suffering from
short bowel syndrome so that their bodies are not dependent upon being
fed totally intravenously.
Less Commonly Known benefits of Hormone Replacement
Therapy include:
- Attempting to induce remission in those who suffer
from Multiple Sclerosis
- Weight loss treatment for those with obesity
- Anti-aging treatment to reverse effects of the aging
process (read more below)
- Combating fibromyalgia
- Relieving ulcerative colitis and Crohn's disease symptoms
- General treatment for being of small stature
- Administration to assist in physical enhancement
for athletics or bodybuilding
Growth Hormone as an anti-aging therapy
The first claims of Growth Hormone as a valid treatment
to combat the aging process dates back to the year 1990. The New England
Journal of Medicine released a study in which Growth Hormone was implemented
to treat twelve males over the age of sixty. At the end of this study,
every male was shown to have increases in lean body mass and bone density
that were of statistical significance. The control set of males showed
no such improvements. The scientists who conducted the research noted
that reduction in bone density and an increase in lean body mass are
among the changes that occur normally over a ten to twenty year period
of aging. Even though the authors did not claim that Growth Hormone
reversed the process of aging, the results that they released were interpreted
incorrectly, leading many to believe that Growth Hormone was effective
as an agent to prevent and reverse aging.
A survey of clinical research conducted by the Stanford
University School of Medicine released in 2007 revealed that Growth
Hormone Replacement Therapy administered to older, yet healthy patients,
led to an increase in muscle mass of around two kilograms. It also led
to a reduction in body fat by two kilograms as well. These effects,
however, were the only positive effects that the survey revealed. Cholesterol
levels, bone density, maximal aerobic capacity, and lipid profiles showed
no change, nor did any other significant factor that would indicate
an increase in general fitness. The survey did not discover gains in
muscle strength. They concluded that Growth Hormone merely allows the
body to store greater amounts of water in muscle tissues, which would
not lead to an increase in the actual growth of the muscles. This also
explains the improved lean body mass as well. Standardized administration
of Growth Hormone did induce several negative issues like pain and swelling
of the joints, carpal tunnel syndrome, and a higher risk of developing
diabetes.
Complications and risks of Growth Hormone therapy: bio identical hormone replacement therapy side effects
With Growth Hormone Replacement Therapy, some adults
may experience the side effects of nerve compression, pain and swelling
of the joints, and water retention. Also, there is a concern that, theoretically,
growth hormone treatment might raise the risk of developing cancer or
diabetes, even more so in individuals who have other risk factors and
take higher doses of Growth Hormone. It should be noted, though, that
diabetes generally develops due to the accumulative effects of bad eating
habits over the course of thirty or forty years. The most probable cause
for diabetes in those patients who undergo Growth Hormone Replacement
Therapy is the lack of proper nutrition that the individual experienced
throughout his or her life. One particular survey of patients who were
administered Growth Hormone that was collected from cadavers as children
were shown to have a modestly higher risk of colon cancer as adults;
however, cadaver Growth Hormone ceased to be used anywhere worldwide
around 1985. Also, a link between the treatment and the incidence of
colon cancer was not adequately established in the survey.
History
Choh Hao Li is associated with the discovery, refinement,
and eventual synthesis of Growth Hormone. The history of the use of
growth hormone from the initial extraction of the hormone from the human
pituitary, to the minor catastrophe that resulted in a small group of
patients acquiring Creutzfeldt-Jakob disease, to the eventual expansion
of use and large expenses of synthetic Growth Hormone is explained in
further detail in more detail elsewhere on Growth Hormone Treatment.
By the year 2005, Growth Hormone of the synthetic
variety was attainable in the U.S. by means of a number of manufacturers.
Among these manufacturers are Genentech (Nutropin), Lilly (Humatrope),
Pfizer (Genotropin), Novo (Norditropin), and Merck Serono (Saizen).
All of these products are almost identical in their composition, cost,
and efficacy. They vary mainly through means of delivery and ultimate
formulation. Also in the year 2005, Teva, a company from Israel, began
to offer Tev-Tropin in the United States for a cheaper price. In the
year 2006, the United States FDA gave the go ahead to a follow-up type
of rhGH known as Omnitrope, released by Sandoz. Alkermes and Genentech
developed a form of Growth Hormone that releases over time known as
Nutropin Depot. This treatment was FDA-approved in 1999 and it minimized
the need for daily injections, requiring one injection every two to
four weeks; however, this product became discontinued in the year 2004.
See also:
Human Growth hormone; Human Growth hormone treatment; Bodybuilding and Human Growth; Hormone Treatment;
Human Growth Hormone controversies; Recombinant protein List; Insulin-Like
Growth Factor-1
References
Alba-Roth, M'ller, Schopohl, von
Werder (Published 1988). Arginine can enhance Human Growth Hormone secretion
through the suppression of internal secretion of somatostatin. Journal
of Clinical Endocrinology and Metabolism Volume 67 Issue 6: Pages 1186-9.
PubMedID 2903866.
Scarth. Controlling the Human
Growth Hormone and-Insulin-Like Growth Factor axis by nutraceutical,
environmental, and pharmaceutical xenobiotics: a new role for enzymes
that metabolize xenobiotics and the factors which regulate their expression.
A review". Xenobiotica Volume 36 (Issue 2-3): Pages 119-218. PubMedID
16702112.
Takahashi, Kipnis, Daughaday (Published
1968). Human Growth Hormone secretion during sleep". Journal of
Clinical Investigation Volume 47 Issue 9: Pages 2079-90. PubMedID 5675428.
Actions of Ant. Pit. Growth Hormones.
Med. Coll of Ga, 2007
King. Growth Hormone. Indiana
SU 2006
Study finds no proof that Human
Growth Hormone Therapy leads to longer life.
British Broadcasting Company News.
July 26, 2002. Human Growth Hormone therapy linked to cancer.
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