Growth hormone

Definition

Growth hormone, also known as somatotropin, is a peptide hormone produced by the anterior pituitary gland that stimulates growth, cell reproduction, and regeneration in humans and other animals. It plays a crucial role in metabolic regulation, influencing processes like protein synthesis, fat metabolism, and glucose homeostasis.

5 Must Know Facts For Your Next Test

1. Growth hormone is secreted in pulses, primarily during sleep, with its levels peaking during deep sleep phases.
2. It promotes the growth of bones and muscles by stimulating protein synthesis and increasing amino acid uptake in tissues.
3. Growth hormone also aids in the metabolism of fats by promoting lipolysis, which helps to decrease fat mass.
4. In addition to its growth-promoting effects, growth hormone helps regulate carbohydrate metabolism by reducing insulin sensitivity and increasing blood glucose levels.
5. Deficiency or excess of growth hormone can lead to various disorders, such as dwarfism in children or acromegaly in adults.

Review Questions

• How does growth hormone influence metabolism, particularly regarding protein and fat metabolism?
  • Growth hormone has a significant impact on metabolism by promoting protein synthesis and encouraging amino acid uptake in tissues. This supports muscle growth and repair. Additionally, it stimulates lipolysis, which breaks down fats into free fatty acids for energy use, thereby reducing fat mass. Together, these actions illustrate how growth hormone integrates both protein and fat metabolism to maintain overall metabolic balance.
• Discuss the role of IGF-1 in mediating the effects of growth hormone on growth and development.
  • IGF-1 plays a pivotal role as a mediator of the actions of growth hormone. When growth hormone is secreted, it stimulates the liver to produce IGF-1, which then circulates in the bloodstream to promote cell division and tissue growth in bones and muscles. This relationship highlights how growth hormone sets off a cascade effect that facilitates physical growth and development through IGF-1 signaling pathways.
• Evaluate the potential consequences of growth hormone deficiencies or excesses on human health and development.
  • Deficiencies in growth hormone can lead to conditions like dwarfism in children, characterized by inadequate height and growth due to insufficient stimulation of bone and muscle development. Conversely, excess growth hormone can result in acromegaly in adults, where there is abnormal enlargement of bones and tissues. Both scenarios illustrate the critical balance required for optimal health; either deficiency or surplus can disrupt normal physiological processes and lead to serious health issues.

Related terms

Insulin:

A hormone produced by the pancreas that regulates glucose levels in the blood and plays a role in fat and protein metabolism.

IGF-1: Insulin-like Growth Factor 1, a hormone produced primarily in the liver that mediates many of the growth-promoting effects of growth hormone.

Hypopituitarism: A condition characterized by reduced secretion of one or more hormones from the pituitary gland, including growth hormone, leading to various growth and metabolic disorders.