Growth hormone can have several effects on the body when it is present in excess or deficient amounts.

Excess growth hormone

One of the most common causes of excess growth hormone is a tumor comprised of somatotroph cells in the anterior pituitary. These are benign adenomas that gradually increase in size producing increasing amounts of growth hormone.

Excess growth hormone causes side effects such as:

• Thickening of bones in the jaws, fingers and toes. The heavy jaw and large digits that result is referred to as acromegaly.
• Sweating
• Pressure on the nerves (e.g. carpal tunnel syndrome)
• Increased sex hormone-binding globulin (SHBG)
• Insulin resistance
• Reduced sexual function
• If a pituitary tumor is growing large, it may cause symptoms such as blurred vision, headache, pressure in the optic nerve and deficiency of other pituitary hormones.

Deficiency of growth hormone

The effects of a deficiency in growth hormone vary according to the age of the affected individual. For example, if the deficiency occurs during childhood it can lead to:

• Growth failure
• Short stature or reduced height
• Delayed sexual maturity

If growth hormone deficiency occurs in adults, it can lead to an increase in fat mass and a decrease in muscle mass, as well as decreased energy levels and therefore a reduced quality of life.

Some of the side effects of artificial human growth hormone, which is used to treat growth hormone deficiency and short stature include:

• Increased risk of diabetes
• Joint swelling
• Carpal tunnel syndrome
• Joint pain
• Immune reaction to growth hormone