Growth Hormone (GH): Definition and Clinical Applications
Growth Hormone (GH) is a polypeptide hormone secreted by somatotroph cells in the anterior pituitary gland that is essential for postnatal growth, metabolism, and systemic homeostasis. 1
Physiological Role and Mechanism of Action
- GH secretion is regulated by hypothalamic neuropeptides, including GH-releasing hormone (GHRH) and somatostatin 1
- GH exerts effects through direct interaction with the growth hormone receptor and indirect pathways mediated by the GH-IGF-I axis 1
- GH receptor activation triggers signaling pathways such as JAK-STAT, PI3K/AKT, and MAPK, promoting cellular proliferation, differentiation, and metabolic balance 1
- The GH-IGF-I axis is critical for bone growth, lipid and carbohydrate metabolism, and organ-specific physiological functions 1
Clinical Indications for GH Therapy
GH therapy is indicated for several conditions in pediatric patients:
- Growth hormone deficiency (congenital or acquired) 2
- Chronic kidney disease (CKD) stages 3-5 or dialysis patients with persistent growth failure 3
- Turner syndrome 2
- Prader-Willi syndrome 2
- Small for gestational age (SGA) without catch-up growth 2
- Idiopathic short stature 2
- SHOX gene haploinsufficiency 2
- Noonan syndrome 2
GH Therapy in Chronic Kidney Disease
For children with CKD, specific recommendations include:
- GH therapy is recommended for children with stage 3-5 CKD or on dialysis aged above 6 months with persistent growth failure (height below third percentile and height velocity below twenty-fifth percentile) 3
- GH should be administered at 0.045-0.05 mg/kg body weight per day via subcutaneous injections in the evening 3
- For transplant recipients, GH therapy should be initiated 1 year after transplantation if spontaneous catch-up growth does not occur 3
- Both reference GH products and biosimilars are recommended for use in short children with CKD 3
Monitoring During GH Therapy
Regular monitoring is essential:
- Clinic visits every 3-6 months to assess stature, height velocity, pubertal development, and skeletal maturation 3
- Laboratory monitoring should include thyroid hormone levels, serum glucose, calcium, phosphate, bicarbonate, and parathyroid hormone levels 3
- If height velocity in the first year of treatment is less than 2 cm per year over baseline, adherence assessment and measurement of IGF-1 levels are recommended 3
When to Discontinue GH Therapy
GH therapy should be stopped in the following circumstances:
- When epiphyseal closure is demonstrated 3
- At the time of renal transplantation 3
- In patients with persistent severe secondary hyperparathyroidism (PTH >500 pg/ml) 3
- With occurrence of intracranial hypertension 3
- In patients with slipped capital femoral epiphysis 3
- If the patient does not adequately respond to GH treatment despite optimal nutritional and metabolic control 3
- In patients with accelerated bone maturation 3
- In case of an unexplained decrease in estimated glomerular filtration rate 3
Potential Side Effects and Complications
- Intracranial hypertension (rare but serious) - requires immediate evaluation if persistent headache or vomiting occurs 4
- Glucose intolerance - increased insulin secretion and hyperinsulinemia may occur during therapy 4
- Secondary hyperparathyroidism - GH might have direct stimulatory effects on the parathyroid gland 3
- Slipped capital femoral epiphysis - requires bone radiographs if symptoms occur 3
Clinical Benefits and Outcomes
- The expected increase in final height after 2-5 years of GH treatment amounts to approximately 7.2 cm 3
- GH therapy improves quality of life, self-esteem, and social rehabilitation in children with growth failure 3
- In CKD patients, GH therapy can overcome the state of GH insensitivity that characterizes advanced kidney disease 3