Test 3: lecture 6 Flashcards
endocrine vs paracrine vs autocrine
endocrine→ secreted, enters blood stream and can act everywhere a receptor is located
paracrine- local hormone control
autocrine- hormone released by cell acts on that same cell
four general classes of hormones
proteins and peptides
steroids
derivatives of tyrosine (amines)
fatty acid derivatives (e.g. prostaglandins)
____hormones are stored in secretory vesicles until needed
Protein and peptide
___hormones are synthesized from cholesterol and are not stored.
Steroid
___hormones are derived from tyrosine and are stored
Amine
peptide hormone synthesis
N-terminal signal peptide tells the golgi apparatus to package these hormones into secretory vesicles for secretion
characteristics of hormone secretion:
Incredibly ____concentration of hormones
_____ feedback control
___ variations in hormone release
low
Negative
Cyclical
____ are dissolved in the plasma (short half-life).
Peptides and catecholamines
(water soluble)
____ hormones are bound to plasma proteins given them a ___ half-life.
Steroid and thyroid
long (don’t get dissolved as quickly)
how are hormones removed from blood
- Binding with tissues
- Metabolic destruction by tissues
- Excretion by liver into the bile
- Excretion by kidneys into the urine
based on how fast they are secreted
protein-bound hormones are cleared slower than free hormones.
three locations for hormone receptors
cell membrane
cytoplasm
nucleus
where are the receptors for peptide and catecholamines
hormone receptor on the cell membrane
water soluble
where are the steroid hormone receptors
in the cytoplasm
where are the thyroid hormone receptors
in the nucleus
one way for a cell to regulate hormones is to ___ the receptors
decrease or increase the number of receptors for a specific hormone
peptide and catecholamines depend on ____ for intracellular signaling
second messengers
Adenylyl cyclase - cAMP
Phospholipids: IP3 and DAG
Calcium-calmodulin
cAMP second messenger
peptide hormone can’t get into cell, binds to receptor on the surface
this causes ATP → cAMP with the help of enzyme adenylyl cyclase
cAMP then is used to activate cAMP dependent protein kinase
which is used to activate protein and produce cell response
cAMP is formed by an amplification step therefore a very small amount of hormone can create very large effect