G is for Growth Hormone

by Dr Daniel Sister

Human Growth Hormone (HGH)

Human Growth Hormone, one of the most abundant hormones, is produced by the pituitary gland, deep inside the brain and secreted in pulses during the initial phases of sleep.

It helps stimulate our body to grow, and is also believed to be important for tissue repair, muscle growth, healing, brain function, physical and mental health, bone strength, energy and metabolism.

When we are young our body produces a great deal of HGH. During the adolescence growth spurt GH levels increase and then decline and remain stable until mid-adulthood. After that levels begin to decrease at approximately 14% per decade until about age 60 when they plateau.

The physiological decrease in GH is thought to be the primary factor in the ageing process. Adult growth hormone deficiency can lead to rapid ageing and a host of symptoms among them: reduced endurance, low sex drive, decreased bone density, decreased muscle mass, and reduced cardiac function, blood sugar control, immunity and memory.

Dr. Daniel Rudman, an endocrinologist, pioneered the original peer reviewed research on Growth Hormone in humans. Dr. Rudman states: “The overall deterioration of the body that comes with growing older is not inevitable. We now realize that some aspects of it can be prevented or reversed┬╗.

His research has documented that increasing growth hormone levels of men over 60 resulted in changes in body composition including lean muscle, fat loss and thickening of skin. Growth Hormone has been shown in other studies to reduce wrinkles, restore size in the pancreas, heart and other organs that shrink with age. HGH has also proven to enhance memory, elevate mood, increase cardiac output, boost immune function, improve vision, restore hair loss, improve energy and increase sexual function.

Research has shown that ageing leads to reduced responsiveness of the precursor hormone GHRH to signals from the hypothalamus. Research also suggests that overall metabolic response to available HGH diminishes due to decreased sensitivity of cellular receptor sites.

Diagnosing GH deficiency and monitoring the therapeutic levels of GH replacement therapy is problematic. Thus, the pharmacological use of GH boosting agents has been proposed to ameliorate the metabolic imbalances associated with Growth Hormone deficiency. Because GH fluctuates radically throughout the day, random serum measurements are unreliable as diagnostic and therapeutic markers.

Fortunately there is a stable biologic mediator of GH, Insulin-Like Growth Factor-1 (IGF-1), readily measurable in serum. IGF-1 or somatomedin C is a protein produced by the liver and released into the blood stream. Its production is controlled by GH release from the pituitary gland, which is in turn controlled by the brain through signals from the hypothalamus.

There is excellent correlation with GH release and extracted IGF-1 measurements from serum; therefore, IGF-1 measurement in the blood is an indirect method of assessing GH levels. As with any indirect measurement, it is imperative to keep in mind that other factors may influence the liver function and, therefore, modulate IGF-1 production.

Other factors known to lower IGF-1 levels include oral estrogens, protein calorie malnutrition, insulin deficiency, liver failure, hypothyroidism, pregnancy, gluco-corticoid therapy, renal failure and acute catabolic stress (eg, surgery, trauma, hip fractures and infectious diseases).

All of these factors are thought to stress the liver and interfere with IGF-1 production. The measurement of random human growth hormone in serum is of very little diagnostic value because levels change dramatically in response to various stimuli. Therefore the measurement of IGF-1 is the best indicator of adult growth hormone deficiency in the outpatient setting, and the test of choice to monitor growth hormone therapy.

While many hormones can be replaced to deter some of the effects of ageing, HGH reaches far beyond the scope of any of the other hormones. Not only does it prevent biological ageing, but it also acts to significantly reverse a broad range of the signs and symptoms associated with the ageing process.

The primary influences on age-related decrease in HGH secretion include reduced production of GHRH and increased production of somatostatin, the hypothalamic inhibitor of HGH release.

Research has demonstrated that HGH therapy can reverse the biological markers of ageing by as much as twenty years within six months of therapy.

It is known that the ageing pituitary somatotroph cells are capable of secreting as much HGH as the young somatotroph cells when they are adequately stimulated.

The problem is not in having insufficient growth hormone as we age. The pituitary has plenty of the hormone in a sequestered state but releases less of the hormone as we age. Natural substances have been identified and documented to stimulate the hypothalamus and pituitary resulting in greater release of growth hormone. These natural substances that stimulate growth hormone release are called secretagogues.

It recent years supplementation with this hormone has become popular because of its purported anti-ageing benefits. Until recently growth hormone therapy has only been available in the form of injections that are very expensive, inconvenient and interfere with the natural secretion of growth hormone

Instead of growth hormone replacement with injections, natural stimulation of growth hormone can be achieved with substances that cause the pituitary to secrete growth hormone. Stimulation of hormone release is safe, effective, and less expensive and will obviously not interfere with the release of one’s growth hormone, as injection therapy does.

Due to the outstanding work of many researchers over the past two decades, several effective, natural HGH secretagogues have been discovered that will stimulate HGH release.

Specific amino acids like Arginine, Ornithine, Lysine, Glutamine, Methionine, Cysteine, Tyrosine and Glycine have been recognized as having a natural stimulatory effect on the pituitary, resulting in the release of HGH.

Oral secretagogue has been found to be a safe and effective HGH therapy capable of improving many of the clinical signs and symptoms associated with the process of ageing. It has been found to be profoundly efficacious as a single therapy and as an adjunct to HGH injections.

The results and efficacy of HGH therapy are strikingly consistent. Untreated HGH deficient adults are shown to have increased cardiovascular mortality, reduced skeletal muscle strength, reduced exercise capacity, reduced glomerular filtration and renal plasma flow, defective thermo-regulation and sweat secretion, reduced energy expenditure and basal metabolic rate, reduced myocardial function, clinical signs of premature atherosclerosis, and abnormal thyroid metabolism (ageing skin, hair, nails). Body composition has been found to be abnormal in these patients, as evidenced by decreased lean body mass, increased fat mass, visceral obesity, reduced bone mineral content, and reduced extra cellular fluid volume, while independent groups have reported impaired psychological well being.

HGH improves utilization of fat as a source of energy by stimulating lipolysis and fat oxidation. The literature contains numerous recent publications on this topic. IGF-1 levels in obesity are high in the presence of low HGH production and high peripheral insulin levels. The levels of IGF-1 fall during low calorific intake and this is accompanied by loss of both muscle and fat.

This increase of IGF-1 is a non growth hormone dependent function and is related to insulin concentration.

HGH affects protein metabolism in a manner that increases lean body mass through stimulation of protein synthesis and reduction of protein oxidation.

Long term IGF-1 deficiency affects carbohydrate metabolism, leading to insulin resistance and exacerbated obesity. These effects can be reversed with HGH therapy. HGH increases glucose turnover, making it more readily available metabolically as a primary fuel

In August 1996, the FDA approved Human Growth Hormone for use in adult patients. But researchers in England investigated the lifetime medical records of children, now adults, who took human growth hormone (HGH) for health reasons during the years between 1959 and 1985 and found that they had a higher rate of developing colon cancer.

Safety and cost considerations associated with growth hormone replacement have generated interest in several research studies focused on oral growth hormone releasers. Because of the English study, there is an ongoing and very spirited debate among scientists, researchers, and physicians regarding this treatment.

Some believe the natural decline in growth hormone production produces an appropriate balance and in fact supplementation may stimulate cancer cells to grow. Others have found that if the dosage administered helps a patient achieve ‘normal’ levels of HGH then it is both safe and effective.