Growth Hormone Secretion – Function & Disorders
Growth hormone secretion refers to the release of growth hormone (GH) from the pituitary gland. It regulates body growth, metabolism, and cell regeneration throughout life.
Things worth knowing about "Growth hormone secretion"
Growth hormone secretion refers to the release of growth hormone (GH) from the pituitary gland. It regulates body growth, metabolism, and cell regeneration throughout life.
What is Growth Hormone Secretion?
Growth hormone secretion is the process by which the pituitary gland (hypophysis) releases growth hormone (GH) into the bloodstream. GH is a peptide hormone that plays a central role in physical growth, metabolic regulation, and tissue repair. Its release does not occur continuously but rather in pulsatile bursts, with the highest secretion occurring during deep sleep in the early hours of the night.
Regulation of Growth Hormone Secretion
GH secretion is controlled by a complex interplay of signaling molecules and feedback mechanisms:
- GHRH (Growth Hormone-Releasing Hormone): Released from the hypothalamus, GHRH stimulates the pituitary gland to secrete GH.
- Somatostatin: Also produced by the hypothalamus, somatostatin inhibits GH release and acts as the physiological counterpart to GHRH.
- IGF-1 (Insulin-like Growth Factor 1): Produced mainly in the liver, IGF-1 provides negative feedback to both the hypothalamus and the pituitary gland, suppressing further GH release.
- Ghrelin: Known as the hunger hormone, ghrelin also promotes GH secretion.
Factors Influencing GH Secretion
Several physiological and external factors affect the amount and frequency of GH release:
- Sleep: The largest secretory burst occurs during the first hours of deep sleep.
- Physical exercise: High-intensity training, especially endurance and resistance exercise, stimulates GH release.
- Nutrition: Fasting and low blood glucose levels promote secretion, while carbohydrate-rich meals suppress it.
- Age: GH secretion peaks during childhood and puberty and declines significantly with age.
- Stress: Both physical and psychological stress can transiently increase GH output.
- Sex: Women tend to have higher GH secretion frequency compared to men.
Biological Effects of Growth Hormone
GH exerts its effects both directly and indirectly through IGF-1:
- Promotion of linear growth in children and adolescents
- Building and maintaining muscle mass
- Breakdown of fat tissue (lipolytic effect)
- Regulation of carbohydrate and protein metabolism
- Support of bone and organ health
- Contribution to wound healing and cellular regeneration
Clinical Relevance: Disorders of Growth Hormone Secretion
Growth Hormone Deficiency (GHD)
A deficiency of GH can be congenital or acquired. In children, it leads to impaired growth and short stature. In adults, it manifests as reduced muscle mass, increased body fat, fatigue, and elevated cardiovascular risk.
Growth Hormone Excess
Excessive GH secretion, most commonly caused by a benign pituitary adenoma, leads to gigantism in children (before growth plate closure) and acromegaly in adults -- a condition characterized by enlargement of the extremities (hands, feet, face) and internal organs.
Diagnosis
Assessment of GH secretion is most commonly performed by measuring IGF-1 serum levels, which are more stable than the pulsatile GH itself. Stimulation tests (e.g., insulin tolerance test) and suppression tests (e.g., oral glucose tolerance test) are also used to identify secretory disorders.
Treatment
Confirmed GH deficiency is treated with recombinant human growth hormone (rhGH) replacement therapy, administered via subcutaneous injection and approved for both children and adults. GH excess is managed through surgical removal of the pituitary adenoma, medical therapy (e.g., somatostatin analogues or GH receptor antagonists), or radiotherapy.
References
- Melmed S. et al. - Williams Textbook of Endocrinology, 14th Edition. Elsevier (2020).
- Giustina A., Veldhuis J.D. - Pathophysiology of the Neuroregulation of Growth Hormone Secretion in Experimental Animals and the Human. Endocrine Reviews, 19(6): 717–797 (1998). PubMed PMID: 9861545.
- World Health Organization (WHO) - Growth Hormone Deficiency and Treatment Guidelines. WHO Technical Report Series (2007).
Most purchased products
For your iron balance
Specially formulated for your iron balance with plant-based curry leaf iron, Lactoferrin CLN®, and natural Vitamin C from rose hips.
For your universal protection
As one of the most valuable proteins in the body, lactoferrin is a natural component of the immune system.
For Healthy Oral Flora & Dental Care
Formulated lozenges with Dentalac®, probiotic lactic acid bacteria, and Lactoferrin CLN®The latest entries
3 Posts in this encyclopedia categorySphingolipid synthesis
Fatty acid receptor
Vitamin kinetics
Most read entries
3 Posts in this encyclopedia categoryMagnesiumcarbonat
Calorie content
Cologne list
Related search terms: Growth hormone secretion