Introduction to Endocrinology - Mechanisms of action of hormones

5 important questions on Introduction to Endocrinology - Mechanisms of action of hormones

What are generally the location for the different types of hormone receptors?

- In or on the surface of the cell membrane - protein, peptide and catecholamine

- In the cell cytoplasm - steroid hormones

- In the cell nucleus - thyroid hormones

What is the difference between down-regulation and up-regualtion of the receptors?

When down-regulation takes place there will be a decrease in active receptors, while up-regulation will lead to an increase in active receptors and intracellular signaling.

What are the different types of receptor complexes?

- Ion channel-linked receptors
- G protein-linked receptors
- Enzyme-linked hormone receptors - e.g. Leptin with tyrosine kinase
- Intracellular hormone receptors and activation of genes
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

Name the 3 second messengers used for mediating intracellular hormonal functions by the different hormones and how they work.

1) cAMP - adenylyl cyclase --> once inside the cell it usually activates a cascade of enzymes.
2) Calcium ions --> upon entering 3/4 calcium ions bind with the protein calmodulin which then changes shape and initiates activation of inhibition of protein kinases.
3) products of membrane phospholipid breakdown --> activate enzyme phospholipid C which catlyzes the breakdown of especially IP3 and PIP2

Steroid hormones and thyroid hormones can also act mainly on the genetic machinery of the cell, what does this result in?

- Steroid hormones increase protein synthesis

- Thyroid hormones increase gene transcription in the cell nucleus

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo