Question

Growth hormone a. Increased protein synthesis; increased cell respiration b. Protein catabolism in muscles; gluconeogenesis in liver c. Protein synthesis in muscles; decreased glucose utilization d. Fall in blood glucose; increased fat synthesis

Short answer

Growth hormone (GH) plays various roles in the body, including increased protein synthesis and increased cell respiration (option a), protein catabolism in muscles and gluconeogenesis in the liver (option b), protein synthesis in muscles and decreased glucose utilization (option c), and a fall in blood glucose levels and increased fat synthesis (option d). All given options accurately describe the effects of GH on different physiological processes.

Step-by-step solution

Understanding Growth Hormone Functions

The growth hormone (GH) is an essential hormone produced by the pituitary gland. It has a broad range of effects, including stimulating growth, cellular reproduction, and cell regeneration in humans and other animals.

Analysing Option (a)

GH encourages protein synthesis in various tissues, leading to cell growth. Increased cell respiration is also a result of enhanced metabolic activity due to GH effects, especially in growing cells.

Analysing Option (b)

GH acts to conserve glucose by facilitating protein catabolism in muscles, which provides alternative energy sources. Furthermore, it stimulates gluconeogenesis in the liver, leading to the production of glucose from non-carbohydrate sources, thus aiding in maintaining blood glucose levels.

Analysing Option (c)

GH promotes protein synthesis in muscles, leading to muscle growth and development. It also decreases glucose utilization by making cells less sensitive to insulin, conserving glucose levels.

Analysing Option (d)

By increasing lipid breakdown and inhibiting glucose uptake in peripheral tissues, GH can result in a fall in blood glucose levels. GH also promotes fat synthesis as it stimulates triglyceride uptake and lipid accumulation in adipocytes.

Summary

All given descriptions are correct roles of growth hormone. It regulates protein synthesis, cell respiration, protein catabolism, gluconeogenesis, decreases glucose utilization, induces a fall in blood glucose levels, and stimulates fat synthesis.

Key concepts

Protein Synthesis

Protein synthesis is a crucial biological process in which cells generate new proteins, essential for cellular function and growth. The growth hormone (GH) plays a significant role in stimulating this process.
GH promotes protein synthesis by increasing the uptake of amino acids into cells, which are the building blocks of proteins. This process is especially important in muscle tissues, where enhanced protein synthesis leads to muscle growth and repair.
Growth hormone influences the synthesis of structural proteins and enzymes, which are necessary for development and metabolic functions. Additionally, GH stimulates ribosomal RNA synthesis, enhancing the protein production capacity of cells.

Gluconeogenesis

Gluconeogenesis is the metabolic pathway that results in the generation of glucose from non-carbohydrate sources, such as amino acids, lactate, and glycerol. The growth hormone facilitates gluconeogenesis, particularly in the liver.
This process is essential when the body requires additional glucose, such as during fasting or intense exercise. By promoting gluconeogenesis, GH helps maintain blood glucose levels and ensures a steady supply of energy.
Moreover, gluconeogenesis is vital for providing glucose to the brain and red blood cells, which rely heavily on glucose as an energy source. Growth hormone's role in this pathway underscores its importance in metabolic regulation.

Cell Respiration

Cell respiration is a fundamental process in which cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), a form of energy that cells use.
Growth hormone enhances cell respiration by increasing metabolic activity. This increase in metabolic activity supports cellular growth and energy production and is particularly prominent in growing and repairing tissues.
By boosting cell respiration, GH ensures that cells have the necessary energy to perform essential functions, thereby supporting overall growth and health.

Glucose Utilization

Glucose utilization refers to the process by which cells uptake and use glucose for energy. Growth hormone influences this by altering how cells utilize glucose.
GH decreases glucose utilization in some tissues by making them less responsive to insulin. This insulin resistance can be advantageous in ensuring glucose is conserved and available for vital functions.
This regulation by growth hormone helps maintain blood glucose levels, particularly during stress or fasting, when glucose needs to be preserved for critical energy-requiring processes.

Fat Synthesis

Fat synthesis, also known as lipogenesis, is the process by which simple sugars are converted into fatty acids and triglycerides. The growth hormone has a complex role in fat metabolism.
While GH promotes lipid breakdown, it simultaneously aids in fat synthesis by stimulating the uptake of triglycerides and promoting lipid accumulation in adipocytes (fat cells).
This dual role helps balance energy storage and consumption, ensuring that fat reserves are available when needed. GH's influence on fat synthesis is part of its broader role in managing energy metabolism and maintaining body composition.