Growth hormone antagonists

Growth hormone antagonists

The latest development in the medical treatment of acromegaly is the use of growth hormone receptor antagonists. The only available member of this family is the competitive antagonist pegvisomant. By selectively binding the GH receptors and thus blocking the action of the endogenous growth hormone molecules, the synthesis of insulin growth factor-1 (IGF-1) and other GH-responsive proteins in the target cells is decreased. The resulting decreased IGF-1 serum levels improve the symptoms of acromegaly.

Pegvisomant has to be administered subcutaneously by daily injections, starting with a dose of 80mg. Dose adjustments are based on IGF-1 serum levels.

The elevated GH levels and decreased IGF-1 levels may cause some physiological changes:

  • tumors that secrete growth hormone (GH) may expand and cause serious complications.
  • GH opposes the effects of insulin on carbohydrate metabolism by decreasing insulin sensitivity; thus, glucose tolerance may improve in some treated patients.
  • functional GH deficiency may occur, despite the presence of elevated serum GH levels.

The most occurring adverse effect is pain on the site of injection. Other common adverse effects are GI-complaints and increased liver enzymes.