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Where Do Recombinant Human Growth Hormones Come From?

Recombinant human growth hormones (rhGH) are synthetic hormones chemically identical to the naturally produced hormones. Before the development of the synthetic form was refined, the hormones were extracted from the anterior lobe of the pituitary gland in cadavers. The hormone promotes growth and increased metabolism of carbohydrates, fat, protein and bone.

  1. Production of Recombinant Human Growth Hormone

    • Synthesis of rhGH first requires replication of the DNA fragment that encodes the "starter" 24 amino acids in the 191-amino acid polypeptide. Complementary DNA copies from messenger RNA sourced from human pituitary cells serve to encode the remaining amino acids. A bacterium, Escherichia coli, serves as the carrier for the complete DNA sequence, allowing synthesis of the rhGH. Commercially available rhGH is known as somatrem and somatropin, the former contains an extra methionine.

    Effects of rhGH

    • In children, rhGH therapy promotes growth in those diagnosed with growth hormone deficiency or advanced renal failure. Due to its effect on the metabolism of fat and protein synthesis, rhGH also reduces fat while increasing lean body mass and muscle mass in malnourished individuals.

      In adults, the anabolic effects of the hormone can treat post-operative patients and burn victims (who are in extremely catabolic physiologic states), renal failure patients, and those with acquired or physiologic deficiency of the hormone.

    Indications and Side Effects

    • The most common use for growth hormone is for children who are short due to deficiency of the hormone. It's also used in the elderly and individuals with AIDS-associated cachexia (wasting) as it increases fat oxidation and allows more efficient protein synthesis and improved nitrogen balance and body mass.

      Prolonged use of the hormone can lead to cardiomegaly (heart enlargement), a precursor to myocardial oxygen demand and increased risk of heart disease. Large doses of rhGH can also result in acromegaly (enlarged facial features and hands), and myopathy, arthritis and osteoporosis.

    Adult Use and Abuse of rhGH

    • Athletes find it encouraging using rhGH as it is effective in treating muscle injuries, and its beneficial effect is especially evident in elderly patients. Supplements containing growth hormone are also popular among people who wish to delay the aging process.

      Its effect on protein synthesis and muscle mass also means that athletes for whom weight is a priority, such as bodybuilders, weight lifters and throwers, tend to abuse it. However, injection of this hormone by athletes is considered a performance-enhancer and therefore illegal. Athletes also risk developing atherosclerosis from persistent use of the hormone.

    Debate and Controversy

    • Although growth hormone is used to make short children grow, opinions are divided as to what a "normal" height is. While a short child is vulnerable to bullying, some physicians argue that it actually calls for a remedy of society's perception of short people. Others opine that short children should receive as much assistance as possible in order to fit into "normal" society.

      This is not an issue with diagnosis of "classic" growth hormone deficiency or chronic renal failure, but the issue is less clear-cut regarding "inadequate secretion," "partial deficiency" or "dysregulation".

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