Receptor-active growth hormone in Laron dwarfism

Area of Science:

• Endocrinology
• Metabolic Disorders
• Molecular Biology

Background:

• Laron dwarfism is a rare genetic disorder characterized by extreme short stature.
• Previous studies suggested a potential defect in growth hormone (GH) action in Laron dwarfism.

Purpose of the Study:

• To investigate the biological activity of human growth hormone (hGH) in patients with Laron dwarfism.
• To assess the presence and activity of hGH in the sera of Laron dwarfism patients using a hepatic radioreceptor assay.

Main Methods:

• Utilized a hepatic radioreceptor assay to detect receptor-active hGH in patient sera.
• Measured both immunoactive and receptor-active hGH levels.
• Administered arginine infusion to one patient to observe hGH response.

Main Results:

• Substantial quantities of receptor-active hGH were detected in the sera of all 7 Laron dwarfism patients studied.
• Arginine infusion in one patient led to a rapid increase in both immunoactive and receptor-active hGH.
• Circulating hGH in these patients demonstrated biological activity.

Conclusions:

• The findings indicate that circulating hGH in Laron dwarfism is biologically active.
• These results support the hypothesis that Laron dwarfism may result from a generalized defect in growth hormone receptors.
• The study highlights the utility of radioreceptor assays in evaluating hormone function in endocrine disorders.