Question

List two hormones that work through the cAMP second messenger.

Short answer

Adrenaline and glucagon.

Step-by-step solution

Understand the cAMP Second Messenger System

The cAMP second messenger system is a mechanism by which cells respond to extracellular signals. When a hormone binds to a receptor on the cell surface, it activates an enzyme called adenylyl cyclase. This enzyme converts ATP to cyclic AMP (cAMP), which then activates other enzymes inside the cell. These enzymes bring about the desired cellular response.

Identify Hormones Using cAMP

Several hormones utilize the cAMP second messenger system to exert their effects. These hormones bind to cell surface receptors and initiate a cascade that results in the production of cAMP.

List Examples of Hormones

Two common examples of hormones that work through the cAMP second messenger system are adrenaline (epinephrine) and glucagon. Adrenaline is involved in the fight or flight response, and glucagon helps regulate blood sugar levels.

Key concepts

Hormones

Hormones are chemical messengers that play a crucial role in coordinating various physiological processes in the body. They are secreted by glands and travel through the bloodstream to reach their target cells or organs.
Once they reach their target, they bind to specific receptors, which may be located on the cell surface or inside the cell. Binding to these receptors triggers a series of intracellular events that lead to the desired response.
Examples of hormones include:

• Adrenaline: Also known as epinephrine, this hormone is produced by the adrenal glands and is a key player in the body's fight-or-flight response.
• Glucagon: Produced by the pancreas, glucagon helps regulate blood glucose levels by promoting the conversion of glycogen to glucose in the liver.

Hormones like adrenaline and glucagon utilize the cAMP second messenger system to exert their effects on target cells.

Adenylyl Cyclase

Adenylyl cyclase is an essential enzyme in the cAMP second messenger system. It is activated when a hormone binds to its receptor on the cell surface.
The activation of adenylyl cyclase is often mediated by a G-protein-coupled receptor (GPCR). Upon activation, adenylyl cyclase converts ATP (adenosine triphosphate) into cyclic AMP (cAMP).
This conversion plays a crucial role in amplifying the hormone's signal, leading to a significant cellular response even from a small number of hormone molecules.
Key points about adenylyl cyclase:

• It is found on the inner side of the cell membrane.
• It is activated by the interaction of hormones and G-proteins.
• The cAMP produced by adenylyl cyclase acts as a second messenger to activate other proteins within the cell.

Overall, adenylyl cyclase is a pivotal component in the cellular signaling pathway, ensuring that extracellular signals are accurately and effectively transmitted inside the cell.

Cellular Signaling

Cellular signaling is the process through which cells communicate with each other and respond to external and internal stimuli. This process involves the transmission of a signal from the outside of a cell to its interior, leading to a specific response.
Key stages of cellular signaling include:

• Signal Reception: A signaling molecule, such as a hormone, binds to a receptor on the cell surface or inside the cell.
• Signal Transduction: This binding activates a series of pathways, often involving second messengers like cAMP, to transmit the signal inside the cell.
• Response: The final stage, where the cell carries out a specific activity, such as altering gene expression, changing enzyme activity, or modifying cellular metabolism.

The cAMP second messenger system is a classic example of how cellular signaling works. In this system:

• Hormones bind to specific receptors on the cell membrane.
• This activates adenylyl cyclase, producing cAMP from ATP.
• cAMP activates protein kinases, which then phosphorylate other proteins to carry out the desired cellular function.

Cellular signaling ensures that cells can adapt to changing conditions and maintain homeostasis within the body. By understanding these processes, we can appreciate how intricately and precisely our bodies function.