What is the human growth hormone (hGH)?
Growth hormone (GH, somatotropic hormone, HGH, somatotropin, somatropin) — a peptide hormone of the anterior pituitary. Growth hormone or somatotropin (Rev. Latin soma – body) got its name because the young people it causes a marked acceleration of linear growth, mainly due to the growth of the long bones of the limbs. Of all the hormones of the pituitary gland it is produced in the largest quantity. Growth hormone is released throughout life. Products of hGH increases at puberty and decreases with age with an average rate of 14% per decade after 20 years.
Functions of HGH
As the name implies, hGH stimulates linear growth and the growth of internal organs. He also has a significant impact on the metabolism of proteins, fats and carbohydrates. When endogenous secretion or the exogenous introduction of short-time effects of hGH are: increased nitrogen retention, the capture of amino acids and protein synthesis in the liver and muscles; increase the capture of glucose and utilization by the muscles; resistance to the lipolytic effect of catecholamines on adipose tissue. In case of permanent appointment hGH decreases glucose utilization, increases lipolysis and contributes to a further increase in muscle mass. As a result, changes in the composition of the body as a whole. Besides, if you assign hGH to adults with its corresponding shortage reduces cholesterol.
- Anabolic effect – causes muscle growth
- Anti-catabolic action – inhibits muscle breakdown
- Reduces body fat
- Regulates energy usage
- Speeds healing
- Has the effect of rejuvenating
- Causes bone growth and increases growth in young people up to 26 years (until the closure of areas of growth), strengthens bones
- Increases the level of glucose in the blood
- Strengthens the immune system
Some of the effects the drug causes itself, but a large part of its effects is mediated by insulin-like growth factor IGF-1 (previously it was called somatomedin C), which is produced by the action of growth hormone in the liver. Almost all of the effects of growth hormone in sports associated with IGF-1. Identified and other insulin-like growth factors, but their dependence on hGH is less certain.
The decrease hGH secretion with age
The secretion of growth hormone steadily decreases with age. It is minimal in the elderly, who have reduced as a baseline, and frequency and amplitude of the peaks of secretion. A baseline level of growth hormone is maximal in early childhood, the amplitude peaks of maximum secretion in adolescents during the period of rapid linear growth and puberty.
Daily rhythms of secretion
Secretion of somatotropin, like many other hormones, occurs periodically and has several peaks during the day (usually the secretion peak occurs every 3-5 hours). The highest peak is observed at night, about an hour after falling asleep.
Health and the anomaly of secretion of hGH
Excessive secretion of GH in childhood causes gigantism. Robert Wadlow, “giant of Alton” had achieved growth of more than 8 feet 11 inches (267 cm).
The result of excessive production of the hGH after the closure of the epiphyses is acromegaly.
Insufficient production of GH in childhood causes low growth.
Deficient GH in adults in many cases remain unrecognized in the past, more carefully studied in recent years. Most frequently this pathology cause of surgery and/or radiation therapy on different types of pituitary tumors. Patients complain of weakness, fatigue and deterioration of health. They have more in comparison with the control group, the reduction in lean body mass and obesity as well as higher mortality from cardiovascular disease.
HGH in sports
Initially, preparations of growth hormone began to be used for medical purpose, however, almost at the same time this hormone is widespread in sports, because of its ability to increase muscle mass and reduce body fat. The first preparations of HGH was a pituitary corpses, and only in 1981 was made a recombinant drug somatotropin.
In 1989, growth hormone was banned by the Olympic Committee.
Despite the fact that the use of growth hormone in athletic purposes is prohibited, in the last decade, sales of the drug increased multiple times. Mainly, the growth hormone used in sports, especially in bodybuilding, where it’s combined with other anabolic drugs.
The main reason for the popularity of HGH in sports is the ability to reduce the amount of subcutaneous fat. In addition, studies have shown that taking growth hormone leads to increased lean muscle mass, connective tissues and increase volume of muscle cells due to the accumulation of fluid.
Another useful effect of growth hormone – decrease in frequency of injuries. This is due to its ability to strengthen bone and connective (tendons, cartilage) tissue. Growth hormone accelerates healing and tissue regeneration after injuries.
Stimulators of growth hormone
The main regulators of secretion of the growth hormone — peptide hormones of the hypothalamus (somatostatin and somatoliberin), which are secreted by neurosecretory cells of the hypothalamus into the portal veins of the pituitary and act directly on somatotrope. However, the balance of these hormones and on secretion of growth hormone is affected by many physiological factors. Scientists have proved that the level of secretion of growth hormone can be increased without the use of hormonal methods.
Peptides are the most potent stimulators of HGH increase concentration:
HGH Frag (176-191)
Exercise (the effect of aerobic training almost 2 times vyrajenie than strength training)
The protein intake
The amino acid arginine
The amino acid glutamine
Creatine has recently been proven that creatine can increase the production of IGF-1
- Davis LL, Trivedi M, Kramer GL, Rush AJ, Orsulak PJ, Akers L, Petty F. Growth hormone response to baclofen: a comparison of 10-mg and 20-mg doses in healthy men. Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, USA.
- Nindl B. C. et al. Twenty-hour growth hormone secretory profiles after aerobic and resistance exercise //Medicine and science in sports and exercise. – 2014.
- Rennie MJ (April 2003). “Claims for the anabolic effects of growth hormone: a case of the emperor’s new clothes?”. Br J Sports Med
- Harvard Health Letter. Harvard Health Publications. 2008-01-01. “Used by athletes to build muscle, human growth hormone may in fact make muscles bigger, but not necessarily stronger. HGH is also marketed as an anti-aging treatment, but there are no data about possible side effects from long-term use.”