Endocrine Abstracts

Introduction: An autosomal recessive illness called the syndrome of familial GH-resistant short stature is characterized by a phenotype that is similar to that of isolated GH deficiency, but with normal or excessive GH production and decreased IGF-I synthesis. When these individuals are treated with GH, neither growth nor a rise in blood somatomedin/IGF-I activity—the mediator of GH’s growth-promoting effects—are stimulated. This suggests that the cause of the growth failure is end organ resistance.

Objective: A high-affinity GH-binding protein found in normal serum appears to be identical to the extracellular domain of the GH receptor. In the serum of people with Laron-type dwarfism, it is typically lacking. The goal of this study is to determine the status of a family with Laron-type dwarfism’s serum GH binding protein.

Method: An open case study was conducted in a family in which four sisters, who ranged in age from four to sixteen, had the Laron-type dwarfism phenotype. Five unrelated girls with dwarfism of the Laron type and those without endocrine abnormalities served as the control samples. By showing elevated blood OH levels and low serum IGF-I levels on an immunoassay, along with a drop in serum IGF-I levels followed by an increase following GH treatment, Laron-type dwarfism was conclusively proven. Gel chromatography on Sephacryi S-100HR gel electrophoresis following covalent cross-linking to lZ5i-GH, Scatchard analysis of ligand binding, and polyacrylamide gel electrophoresis were used to characterise serum GHbinding proteins.

Results: The GH-binding protein activity in the serum of all family members was similar in affinity. In the same way that normal persons do, calculate the amounts and apparent affinity for OH. The unrelated youngster who had Laron type dwarfism and prior findings of blood OH-binding protein levels in this disorder contrasted this with the very low serum GH binding protein activity in that child.

Conclusions: Since normal cell responsiveness to GH is not required for the production of normal levels of serum GH-BP, it follows that serum GH-BP levels shouldn’t be regarded as a quantitative indicator of GH receptor activity or GH bioactivity. When blood GH-binding protein levels are normal, the affected patients may have a unique metabolic abnormality that causes OH resistance and diminished IGF-l synthesis.