Synergy and Hormone Targeting Flashcards
Describe the process of synergy
When two hormones act together, they don’t have an added effect, they interact with one another to have an even bigger effect
Give an example of synergy occurring
Thyroid hormone and epinephrine both cause very small amounts of fatty acids to be released from lipocytes but when they are both used, they interact with each other and causes a really large amount of fatty acids being released.
What is the key thing about synergy?
the maximum combined response is bigger than the addition of the maximum individual responses
Describe the process of hormone targeting
A secretory cell releases a chemical messenger which is able to cause an effect on the cell which expresses the receptor for that specific messenger. However, the messenger just diffuses randomly and sometimes it reaches the right receptor
Explain why the target cell is self selecting
the secretory cell doesn’t chose the target cell, it just releases the chemical messenger which goes everywhere to ensure efficiency and the target cell choses to have receptors for that hormone
What does the sensitivity of a target cell depend on?
the number of receptors expressed
Why are receptors constantly degraded and synthesised?
to ensure efficiency
What is the process of upregulation?
this is when the synthesis of receptors on the cell surface exceeds the degradation which increases the number of receptors expressed
Does up regulation increase or decrease sensitivity?
it increases it
What is the process of down-regulation?
this is when the degradation of receptors exceeds the synthesis of receptors which decreases the number of receptors
Does down-regulation increase of decrease sensitivity?
decrease
Receptor up-regulation makes a target cell more sensitive to a hormone BECAUSE receptor up-regulation makes more of the hormone receptors available for hormone binding
both statements are true, and the second statement causes the first
