Endocrinology Flashcards

This set of flashcards covers key concepts in endocrinology, focusing on hormone mechanisms, receptors, and actions.

What are the two types of hormone receptors?

Cell surface receptors and nuclear receptors.

What is the function of G-protein coupled receptors?

They couple receptors to adjacent effector molecules and initiate production of second messengers.

How do steroid hormones exert their action?

They bind to specific intracellular receptors and initiate gene transcription.

What does cAMP do in hormone signaling?

cAMP activates protein kinase A, which phosphorylates specific proteins for physiological effects.

What is the role of calcium in cell signaling?

Calcium binds to calmodulin, activating myosin kinase and facilitating smooth muscle contraction.

What happens when a hormone binds to a receptor on a growth factor receptor?

Tyrosine kinase is activated, leading to autophosphorylation and downstream signaling.

What are ligand-regulated transporters?

Receptors that bind ligands and open channels for ion flow, acting as second messengers.

What is metabolic clearance rate?

The rate of disappearance of a hormone from plasma divided by its concentration in plasma.

What is the first step in the action of steroid hormones?

Steroid hormones diffuse across the cell membrane and bind to cytosolic or nuclear receptors.

How do thyroid hormones act in the target cells?

They are converted to T3 in the cytoplasm, bind to nuclear receptors, and activate gene transcription.