Growth hormone

July 22, 2019

Effects on body functions

The growth hormone (somatropin, somatotropin, or HGH) is the body’s peptide hormone, consisting of 191 amino acids and secreted from the anterior pituitary gland. The anterior pituitary produces the growth hormone in spurts and the concentrations vary considerably during the day. Most of the daily growth hormone is produced 1–2 hours after falling asleep. The concentrations of the naturally produced growth hormone are affected by a number of stimuli, such as age, gender, the body constitution, exercise, nutrition and sleep [1, 2].

The growth hormone regulates growth among other things. The growth hormone affects the body through the insulin-like growth factors (IGF-1) produced mainly in the liver. The growth hormone also has effects that do not depend on IGF. Some of the effects are even contrary to those of IGF. One example of such is the effect on the blood sugar. The anabolic effect of the growth hormone is not entirely independent, however; rather, it requires IGF-1 in order to function effectively [3, 4].

The growth hormone has many kinds of effects on the metabolisms of carbohydrates and fat. The growth hormone is an anabolic (i.e. tissue-building) hormone that increases the transport of certain amino acids to cells and accelerates protein synthesis and affects the fat metabolism and the fluid balance of the body. The growth hormone enhances the muscle-growing effects of testosterone and anabolic steroids [5].

Production methods

All of the growth hormone preparations that are licensed in Finland are produced by recombinant DNA-technology.

Selling the growth hormone of human origin (i.e. made from the pituitary glands of deceased individuals) has been prohibited in Finland since 1988 due to the risk of the fatal Creutzfeldt-Jacob’s disease associated with it. The growth hormone of human origin has been sold on the black market, often camouflaged into a growth hormone manufactured by recombinant DNA-technology.

Dosage in medical use

The growth hormone dosage in medical use varies according to the disease being treated and its severity. When treating growth hormone deficiency in adults, the recommended initial dose is 0.15–0.3 milligrams (approximately 0.5–1 IU). In long-term treatment, the recommended dose is a maximum of 1–1.3 milligrams a day (3–4 IU/24 hrs). The average adult’s therapeutic dose of the growth hormone is 0.67 milligrams per day (2 IU/24 hrs).

Medical use

Pursuant to decree 705/2002, referred to in Chapter 44, Section 16 of the Finnish Criminal Code, the growth hormone is a doping substance. The growth hormone is a prescription drug that can be prescribed only by doctors who specialize in endocrinology, pediatric endocrinology or pediatric nephrology.

In the field of medicine, the growth hormone is mainly used for the treatment of growth disturbances caused by insufficient growth hormone secretion in children. Sometimes adults with remarkable growth hormone deficiency are treated with the growth hormone as well.

Before starting the use of the growth hormone, the diagnosis must be carefully ascertained by exercise stress tests that measure the growth hormone secretion. Doctors can be found guilty of malpractice if they prescribe the growth hormone to patients without seeing them or without careful diagnosis.

Patients receiving the growth hormone must be monitored carefully, for example, by subjecting the patient to thyroid gland function tests and examinations for the possibility of glucose intolerance (i.e. sugar metabolism disorder). It is recommended that the growth hormone dosage is checked every six months.

Abuse

The growth hormone is used for its anabolic effects [6, 7]. It is thought to increase muscle mass and strength, to help the body adjust to heavy physical exertion, and to accelerate the healing of injuries. The growth hormone is rarely used by itself. It is often used together with anabolic steroids, insulin and IGF-1. The growth hormone can also be used on the assumption that it would reduce the changes brought about by ageing and improve skin quality.

In addition to the anabolic effect, the growth hormone has a fat-burning effect because it increases the breakdown of triglycerides and reduces the storage of fat [1]. Even professional cyclists have used the growth hormone due to its lipolytic effect to reduce body fat [8].

The growth hormone is a popular doping substance, but scientists have not been able to clinically prove its performance capacity-enhancing effect in full [3]. The main finding of a systematic review and meta-analysis published in 2017 was that the growth hormone increases fat-free mass to a reasonable extent and does reduce fat, but that it does not increase muscle strength or improve aerobic capacity in healthy young people. The added fat-free mass may mostly be caused by the accumulation of fluid. The greatest benefit of the growth hormone is probably obtained from the acceleration of recovery and the prevention of injuries due to the added collagen synthesis [9]. Moderate doses of the growth hormone alone were used in this study. Often, abused doses are higher and the growth hormone is used together with other anabolic substances. The potential effects are then different. However, the growth hormone functions very well in the case of a person suffering from a growth hormone deficiency [8].

Growth hormone use has probably increased due to its cheapened price and the ease of ordering online. The growth hormone can no longer be regarded as a doping substance of the elite athletes only [10].

Adverse effects

When the growth hormone is used in appropriate therapeutic doses, the most common adverse effects include joint and muscle pains and various types of swellings caused by fluid retention. The swellings may lead, among other things, to the increase of intracranial pressure or macular edema. Alternatively, they can lead to carpal tunnel syndrome.

Acute overdosing can first cause hypoglycemia (i.e. low blood sugar) and then even coma. Later on, the consequence is hyperglycemia (i.e. high blood sugar). Long-term use can cause hypertension, cardiomyopathies, diabetes and acromegaly (i.e. the excessive growth of the cartilages, the fingers and the chin) and roughening and thickening of the skin. The risk of certain cancers may grow (for instance, the risk of thyroid, breast and prostate cancers), but this is not certain [5, 6, 7, 11, 12, 13].

Some known trade names (9/2014): Omnitrope, Genotropin.

Timo Seppälä
Medical Director
Finnish Center for Integrity in Sports FINCIS (previously the Finnish Antidoping Agency FINADA)

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Dopinglinkki