Dr. Rob Murray

If your pituitary is damaged the first hormone to be lost is Growth hormone (GH). The causes of GH deficiency can be:

• Idiopathic - unknown cause (usually in children)
• Pituitary and parasellar tumours (common in adults)
• Radiotherapy

The following can have an effect on your Growth Hormone levels:

• Insulin production
• Thyroid levels
• Nutritional state (body weight)

Females secrete up to 3 times as much GH than men and the more we (males & females) weigh the less GH we secrete. 75% of GH is released in the first 3-4 hours of sleep at night

Diagnosing GH deficiency

In children this is fairly straightforward as clinicians know what it is due to normal growth ranges and treatment defines if it's the right diagnosis - give GH and child will grow.

In adults a biochemical diagnosis is needed as physical symptoms could be due to other things e.g., depression, anaemia, etc. The tests would include looking at IGF (Insulin-like growth factor) the levels of IGF in the blood are controlled by GH secretion.

Definition of GH Deficiency in adults

• Impaired quality of life (30/50 % of patients)
• Increased fat -particular on trunk
• Reduced muscle - which can limit exercise and strength
• Impaired heart function (heart is muscle)
• Increased cholesterol
• Impaired immune system (enables the body to fight infection)

From a patients' perspective many symptoms of GH deficiency in adults are subtle, including: loss of vitality, lack of energy, and difficulty in carrying out normal physical activity. It is not known amongst the general population which adults are GH deficient; testing would only be carried out on people with diagnosed pituitary problems.

GH History

• Pre-1985 there were limited supplies, in fact never enough, of pituitary-derived GH
• In 1985 techniques were developed to isolate the gene responsible.
• In 1986 pituitary-derived GH was withdrawn and a biosynthetic GH is now used. This is produced by inserting the GH gene into bacteria. These cells then grow and replicate and identical copy of human GH. GH is then extracted and stored as powder - which is then mixed by you with sterile water in your injecting device.