Function tests

Suspicion of growth hormone deficiency

In patients with severe liver or kidney diseases or acidosis, the arginine stimulation test should not be carried out.

Intravenous application of arginine-.hydrochloride leads to growth-hormone-release (STH) from the anterior lobe of the pituitary gland and to somatostatin suppression.

Growth hormone (STH) and blood glucose

2 ml serum each

Patient resting in supine position over night until mornings 8 o’clock.

• First blood collection empty-stomached for STH and blood glucose 30 min before L-arginine-hydrochloride (-30 min value).
• Infusion of L-arginine-hydrochloride 0,5 g/kg body weight (maximal dose 40g) (mix calculated volume of required Arginine-hydrochloride with same amount of aqua inject).
• Further blood collections after 30 min, 45 min, 60 min, 90 min and 120 min for STH and blood glucose.

An increase in STH-values > 7,5 µg/l makes a growth hormone deficiency in both children and adults unlikely.

In adults, a second confirmation test, for example with GHRH stimulation, which can be carried out at the same time as the arginine STH stimulation test, or an additional glucagon stimulation test is recommended. In children, the glucagon stimulation test can be used instead of the arginine STH stimulation test. A GHRH stimulation test is not recommended in children, as the cause for the frequently occurring idiopathic growth hormone deficiency is often hypothalamic and therefore leads to false negative results in the GHRH stimulation test.

For the definite exclusion of growth hormone deficiency in adults, the insulin tolerance test is best suitable.