Growth Hormone

Definition

Growth hormone, also known as somatotropin, is a peptide hormone produced by the anterior pituitary gland that plays a crucial role in growth, metabolism, and body composition. It stimulates growth in almost all tissues of the body, particularly bone and muscle, and is essential for normal physical development and metabolic functions during periods of stress or injury.

5 Must Know Facts For Your Next Test

1. Growth hormone secretion is pulsatile, with levels peaking during sleep, particularly during deep sleep stages.
2. During periods of stress or injury, growth hormone levels typically increase to support tissue repair and metabolic adjustments.
3. Excess levels of growth hormone can lead to acromegaly, characterized by abnormal growth of bones and tissues, while deficiency can result in stunted growth in children.
4. Growth hormone influences protein synthesis, promotes lipolysis (fat breakdown), and helps regulate carbohydrate metabolism by increasing insulin resistance.
5. In critically ill patients, elevated growth hormone levels may aid recovery but also indicate a heightened metabolic state that must be managed carefully.

Review Questions

• How does growth hormone contribute to metabolic changes during periods of stress or injury?
  • Growth hormone plays a vital role in managing the body's metabolic response to stress and injury by promoting tissue repair and adjusting metabolism. When the body experiences stress or injury, growth hormone levels increase, enhancing protein synthesis for muscle repair and stimulating lipolysis to provide energy from fat stores. This metabolic shift helps ensure that adequate resources are available for healing while supporting the maintenance of blood glucose levels.
• What are the potential consequences of abnormal growth hormone levels in relation to overall health?
  • Abnormal levels of growth hormone can lead to significant health issues. Excessive growth hormone can cause acromegaly, leading to enlarged bones and tissues, which can result in cardiovascular problems and diabetes. On the other hand, a deficiency can hinder proper growth in children and lead to increased body fat and decreased muscle mass in adults. Both conditions underline the importance of maintaining balanced growth hormone levels for optimal health.
• Evaluate the relationship between growth hormone and insulin-like growth factor 1 (IGF-1) in regulating growth and metabolism.
  • Growth hormone and IGF-1 work together closely to regulate growth and metabolism. When growth hormone is released from the pituitary gland, it stimulates the liver to produce IGF-1, which then acts on various tissues to promote growth and development. IGF-1 mediates many anabolic effects of growth hormone, including increased protein synthesis and cellular proliferation. This relationship highlights how both hormones are crucial for maintaining homeostasis during periods of stress or injury while also contributing to long-term physical development.

Related terms

Insulin-like Growth Factor 1 (IGF-1): A hormone produced primarily in the liver that mediates many of the effects of growth hormone on growth and metabolism.

Cortisol: A steroid hormone released in response to stress that can have catabolic effects on tissues and counteract some actions of growth hormone.

Metabolic Syndrome: A cluster of conditions that increase the risk of heart disease, stroke, and diabetes, often linked to dysregulation of hormones including growth hormone.