Oral clonidine-an effective growth hormone-releasing agent in prepubertal subjects

Area of Science:

• Pediatric Endocrinology
• Growth Hormone Physiology
• Pharmacological Stimulation Tests

Background:

• Assessing growth hormone (GH) secretion is crucial for diagnosing growth disorders in children.
• Prepubertal short stature requires reliable methods to evaluate GH neuroendocrine reserve.
• Insulin, clonidine, and metoclopramide are commonly used agents for GH stimulation, but their efficacy varies.

Purpose of the Study:

• To compare the efficacy of clonidine, metoclopramide, and insulin in stimulating growth hormone (GH), cortisol, and glucose levels.
• To evaluate these agents in both healthy prepubertal children and those with GH deficiency.
• To determine the most suitable agent for assessing GH reserve in prepubertal children.

Main Methods:

• Seventeen healthy short prepubertal children (Group A) and five prepubertal GH-deficient children (Group B) were studied.
• Blood samples were analyzed for growth hormone, cortisol, and glucose concentrations after administration of clonidine, metoclopramide, or insulin.
• Peak serum GH levels and changes in cortisol and glucose were compared across stimuli and groups.

Main Results:

• Peak serum growth hormone levels were significantly higher after insulin and clonidine compared to metoclopramide.
• No significant GH increase was observed in GH-deficient children (Group B) with any stimulus.
• Cortisol levels increased with insulin and decreased with clonidine, but remained unchanged with metoclopramide; glucose levels were unaffected by clonidine or metoclopramide.

Conclusions:

• Clonidine is a reliable, sensitive, and safe outpatient test for evaluating growth hormone reserve in prepubertal children.
• Metoclopramide is not a suitable agent for stimulating growth hormone release in this pediatric age group.
• Insulin also demonstrates efficacy in stimulating GH release, alongside its known effects on cortisol.