Growth hormone (GH)

Definition

Growth hormone (GH) is a peptide hormone produced by the anterior pituitary gland that stimulates growth, cell reproduction, and regeneration in humans and other animals. GH plays a crucial role in the regulation of body composition, muscle and bone growth, and metabolism, acting on various tissues throughout the body. Its release is primarily controlled by the hypothalamus through the secretion of growth hormone-releasing hormone (GHRH) and somatostatin, establishing a critical link in the hypothalamic-pituitary axis.

5 Must Know Facts For Your Next Test

1. Growth hormone promotes longitudinal bone growth during childhood and adolescence, ensuring proper skeletal development.
2. In adults, GH influences metabolism by promoting protein synthesis, fat breakdown, and maintaining muscle mass.
3. GH levels fluctuate throughout the day, peaking during sleep, which is essential for its role in growth and repair.
4. Excessive secretion of GH can lead to acromegaly, a condition characterized by abnormal growth of bones and tissues.
5. Deficiency in GH during childhood can result in stunted growth and delayed physical development.

Review Questions

• How does growth hormone interact with other hormones to regulate growth and metabolism?
  • Growth hormone interacts with insulin-like growth factor 1 (IGF-1) to mediate its effects on growth and metabolism. When GH is secreted from the anterior pituitary, it stimulates the liver to produce IGF-1, which promotes cell division and tissue growth. Additionally, GH affects insulin sensitivity and lipid metabolism, illustrating how it works with other hormones to maintain overall homeostasis in body growth and energy regulation.
• Evaluate the role of somatostatin in the regulation of growth hormone secretion.
  • Somatostatin plays a vital role in regulating growth hormone secretion by inhibiting its release from the anterior pituitary gland. Produced by the hypothalamus, somatostatin counteracts the action of growth hormone-releasing hormone (GHRH), creating a balance in GH levels. This regulation ensures that GH is secreted appropriately based on physiological needs, highlighting how interconnected endocrine signals govern hormonal activity.
• Discuss how abnormalities in growth hormone levels can impact an individual's health across their lifespan.
  • Abnormalities in growth hormone levels can have significant health implications at different life stages. In children, GH deficiency leads to stunted growth and developmental delays, while excess GH can result in gigantism. In adults, low GH levels may contribute to increased fat mass and decreased muscle strength, affecting quality of life. Conversely, high GH can lead to acromegaly, resulting in severe metabolic disorders. Understanding these conditions underscores the importance of balanced GH levels for overall health throughout an individual's lifespan.

Related terms

Somatostatin: A hormone produced by the hypothalamus that inhibits the release of growth hormone from the anterior pituitary gland.

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

Hypothalamic-Pituitary Axis: A complex set of interactions between the hypothalamus and the pituitary gland that regulates various hormonal functions in the body.