Exam 3 Review Session ENDOCRINE Flashcards
what are the four main classes of hormones
steroids
monoamines
peptides
glycoproteins
what are steroids derived from
cholesterol
What are amino acids derived from
tyrosine and tryptophan
what are glycoproteins?
proteins bound to a carbohydrate group
what does a prepro hormone contain?
Signal sequence
B section
Connecting polypeptide
A section
What does a pro hormone contain
B section
Connecting polypeptide
A section
and then
just B and A section
No signal sequence, protein is folding, then connecting polypeptide is cut out.
What is a prehormone
inactive until chemically modified in target cell
Hydrophilic messenger
exocytosed by cell, enter blood and travel through blood as is
hydrophobic messenger
diffuse out of endocrine cell and bound to carrier protein within the blood. 1% will travel freely
What kind of receptor binds hydrophilic hormones that cannot cross the plasma membrane?
Extracellular receptors
What type of receptor uses a second-messenger
extracellular receptors
what receptor translocates to the nucleus
intracellular receptor
what receptor bind hydrophobic hormones that can cross the plasma membrane
intracellular
What is necessary in carrier receptor protein for it to cause genetic transcription that turns DNA to mRNA
two half receptors, it’s a homodimer.
Explain how steroid hormones work
carrier protein brings it to the cell, it freely dissociates and enters the cell alone, where it binds the receptor protein, it then translocate into the nucleus, binds the DNA, causes transcription to occur to form mRNA, protein synthesis occurs, then steroid hormone response
What is the difference in the action of a thyroid hormone and a steroid hormone
the thyroid hormone when it enters the cell, binds a “binding protein” and then enters the nucleus alone and binds to the receptor protein in the nucleus
How receptors do thyroid hormones use
two different ones: RXR receptor and TR receptor
What are the two different ways to have second messenger action?
Adenylate Cyclase system (cAMP)
Phospholipase C-Ca2+ System
Tyrosine Kinase
cAMP system
some hydrophilic because it binds extracellular
G coupled
alpha binds adenylate cyclase converting ATP to cyclic AMP which effects the protein kinases that activates or inactivates stuff
Phospholipase C-Ca2+ System
Hydrophilic
G coupled
G protein subunit dissociates and goes to Phospholipase C and breaks down a phospholipid into DAG and IP3 (which goes to ER and causes Ca2+ release)
What uses the tyrosine kinase system
insulin
Tyrosine Kinase System
insulin binds to homodimer which causes auto phosphorylation of dimers in the intracellular side. Then we get phosphorylation of an insulin receptor substrate……end result is glucose update into the cell.
What are the adenohypophysis (anterior) and hypothalamus connected by?
Hypophyseal portal systems
where is the primary capillary bed of the anterior pituitary gland?
at the top of the stalk, secondary is in the lobe
