Midterm 2 - Principles of Hormone Action Flashcards
where are hormones secreted
into blood
where do hormones act
at a distance from the release site
what do hormones need to be able to do
travel in the blood (solubility)
survive long enough
be active at the target site
what do hormones trigger
specific actions in specific target cells
what is the requirement for specific recognition
receptors
what is the principle of action based on
hormone biochemical structure and properties
what are the key to hormone action
receptors
what initiate the effects of hormones
the hormones bind to receptors
what do lipophilic hormones do
diffuse out of producing cells
circulate mainly bound to carriers in the blood
diffuse in target cells to intracellular receptors
what do water-soluble hormones do
they are secreted via exocytosis
they circulate freely in blood
stay out of target cell to surface (extracellular) receptor
what are examples of lipophilic hormones
steroid hormones
thyroid hormones
are lipophilic hormones soluble in water
no, circulate associated to carrier proteins
types of carriers for lipophilic hormones
specific
non specific
examples of specific lipophilic hormone carriers
globulins:
CBG
DBG
SHBG
TBG
examples of non-specific lipophilic hormone carriers
albumin
pre albumin
what are some reasonings for carrier proteins being big
they keep hormones in vessel
prevent hormone degradation
does all of a lipophilic hormone get carried
no - a small portion remains free and diffuses to the tissues
what is the free lipophilic hormone characteristics
the active portion, but also susceptible to degradation
what is the free form (active) lipophilic hormone involved in
feedback loops
what does the carrier serve as
hormone reservoir
hormone buffer
hormone protection
what do carrier proteins play a major role in
controlling lipophilic hormones
in nuclear hormone receptors, what does the ligand binding domain do
binds hormone
in nuclear hormone receptors, what does the DNA binding domain do
binds the DNA of target gene
in nuclear hormone receptors, what does the activation domain do
stimulates gene transcription