Lecture 27 Flashcards
Three primary chemical classes of hormones
1.
2.
3.
- __________ and __________ (except _____) are WATER soluble
- ____________ are LIPID soluble
- Steroids
- Peptides
- Monoamines
- Peptides and monoamines (TH)
- Steroids
Steroid hormones:
- Source= _________ and ________ (also the ___________ produce calcitriol)
- Derivatives of _____________
- Water-insoluble (__________)
- Transported by ________ ____________ through water-based blood stream
- adrenal cortex; gonads; kidneys
- cholesterol
- hydrophobic
- carrier proteins
Steroid hormones:
- Receptor in the ______ or ________ (inside the cell)
- hormones _______ through mb (since they are lipid-soluble)
- _________ effects (activating/inhibiting transcription of specific genes)–> takes _____ to _____ to show up
- cytosol; nucleus
- diffuse
- genomic; hrs; days
Peptide hormones:
- chains of ______ _________
- lipophobic & water-soluble (_____________)
- they bind to ____ __________ receptors
- amino acids
- hydrophilic
- cell surface
- ____ & _____ produced by the hypothalamus
AND - most hormones of the _________ ________
both are classified as _____________ hormones
- RH; IH
- anterior pituitary
peptide
Monoamine hormones:
- derived from the amino acids ________ or ____________
- they behavior similarly to _________ hormones (except TH)
- tyrosine; tryptophan
- peptide
Monoamine hormones derived from…
- tyrosine= __________, ____________, and _____________
- tryptophan= ______________
- epinephrine; norepinephrine; TH
- melatonin
TH is monoamine hormone because it is derived from ________, but they behave similarly to __________ hormones because they are __________ and bind to intracellular receptors
tyrosine; steroid; lipid soluble
Examples of Steroid Hormones
1.
2.
3.
4.
5.
6.
- Calcitriol
- Cortisol
- DHEA
- Testosterone
- Estrogen
- Progesterone
Examples of Peptide Hormones
1.
2.
3.
4.
5.
6.
- GnHR
- GH
- ADH
- Insulin
- CRH
- Oxytocin
Examples of Monoamine Hormones
1.
2.
3.
- Melatonin
- Epinephrine
- TH
- Water-soluble hormones are synthesized then stored in ________ ___________ in the cell
- They DON’NT need transporter proteins since blood is mostly water, so they travel _______
- They CAN’T cross the membrane because it is made up lipids so they bind to a specific _____ ________ receptor
- secretory vesicles
- freely
- cell surface
__________________: a series of events that occur within a cell due to the binding of a signaling molecule (ligand) to a receptor on the cell surface or inside of cell
Signal transduction pathway
Two signaling pathways associated with hormones that employ G-protein coupled receptors (GPCRs)
1.
2.
- receptors are termed GPCRs because they have a ____ __________ attached to them
- the first messenger= ____________
- cAMP
- DAG-IP3
- G protein
- Hormones
G-protein has _____ subunits
- G protein _______ subunit binds either GTP or GDP
depending on if the G protein is active or inactive (no hormone bound)
- active G protein binds _____
- inactive G protein binds ___
3
- alpha
- GTP
- GDP
In cAMP pathway…
- Upon ligand binding to receptor and G protein activation, ______ physically replaces GDP bound to the alpha subunit, which ________
GTP; dissociates
In cAMP pathway…
GTP-bound alpha subunit activates _________ ________, a membrane-associated enzyme that catalyzes _________ of the 2nd messenger ______ from molecules of ATP
adenylyl cyclase; synthesis; cAMP
In cAMP pathway…
- cAMP activates protein __________ (enzymes that attach phosphates to other molecules
- PK phosphorylates enzymes: _______/_______
- Altered enzymes activity causes a _______________
- kinases
- activates/deactivates
- Cell Response
In DAG-IP3 pathway…
- After hormone binds to GPCR and G protein activation
- The G protein activates _________________ enzyme
- This enzyme splits a membrane phospholipid into 2 fragments: ____ & _______ (2nd messengers)
- phospholipase (PLC)
- DAG & IP3
DAG stands for _________
IP3 stands for __________
-DAG activates _____
-IP3 increases intracellular _____ ions (in the cytosol)
Diacylglycerol
Inositol Triphosphate
- PK
- Ca2+
Increased levels of Ca2+ consequences:
- Calcium-dependent cytoplasmic _______ that alter cell __________
- ___________ (protein) can activate PK
- Membrane __________ (opening/closing)
- enzymes; metabolism
- Calmodulin
- channels
___________________ (relative quick): smooth ms contraction, protein synthesis, secretion, mitosis, etc.
metabolic effects
Three types of stimuli that control production and secretion of hormones
1.
2.
3.
- Humoral
- Neural
- Hormonal
Hormone release caused by altered levels of certain critical ions or nutrients (in blood)
humoral stimulus
Hormone release caused by neural input
neural stimulus
Hormone release caused by another hormone (a tropic hormone)
hormonal stimulus
Low Ca2+ in blood is a _________ stimulus
humoral
Action potential in preganglionic sympathetic fibers to adrenal medulla is a ____________ stimulus and the response is to secrete EPI/NOREPI
neural
Hormones from hypothalamus is a _____________ stimulus and the response is the anterior pituitary gland secreted H that stimulate other endocrine glands to secrete H
hormonal
When high levels of thyroid hormones (T4, T3) inhibit the secretion of TSH and TRH the name for this type of hormone regulation is called
negative feedback loop (pathway)
Negative feedback loop for increased levels of cortisol in blood
- elevated levels of cortisol leads to the __________ of the release of both hypothalamic hormone ______ and pituitary hormone _______
- suppression; CRH; ACTH
_________ __________: the receptor for one hormone will NOT bind other hormones. Each hormone has a specific molecular structure that allows it to bind to a particular type of receptor (lock and key)
hormone specificity
_____________: condition in which all the receptor molecules are occupied by hormone molecules- adding more hormone CANNOT produce any greater effect once this is reached
saturation
__________ ____________: refers to the removal or elimination of hormones from the bloodstream effectively reducing their concentration
hormone clearance
- ___________________: the rate of hormonal removal
- ____________: the length of time required to clear 50% of the hormone from blood
- metabolic clearance rate (MCR)
- half-life (t1/2)
Target cells can adjust their sensitivity to a hormone by changing the number of _____________ for it
receptors
Target cell expresses limited number of receptors= ________ sensitivity
- This can be changed by _____-___________ the number of receptors= __________ sensitivity therefore leading to a __________ response
low
-up-regulating; high; STRONG
Target cell expresses an abundance of receptor molecules= _______ sensitivity
- this can be changed by _____-____________ the number of receptors= _____ sensitivity therefore leading to a ____________ response
high
- down-regulating; low; diminished
_____________ effects: when a hormone opposes or reverses the effect of another hormone
antagonistic
_____________ effects: one hormone must be present in order for another hormone to exert its full effects
permissive
__________ (__________) effects: two or more hormones produce the same effect in a target cell and their result together are amplified
additive (synergistic)
What type of hormonal interaction characterizes the relationship between insulin and glucagon at the level of liver cells?
antagonistic
In the absence of TH, epinephrine has a weak affect since TH increases the expression of beta-receptors. What type of hormonal interaction is this?
permissive
Both glucagon and epinephrine cause the liver to release glucose to the blood. When they act together, the amount of glucose realized is about 150% of what is released when each hormone acts alone. What type of hormonal interaction is this?
additive (synergistic)
Four types of cell signaling (or cell communication mechanisms)
1.
2.
3.
4.
- Paracrine
- Autocrine
- Endocrine
- Direct
__________ signals diffuse only to nearby cells in the same tissue or organ
- extracellular signaling molecule
paracrine
_________ signaling: involves the release of hormones in the bloodstream to reach target cells
endocrine
________ signals stimulate the same cell that secretes them
autocrine
_________ signaling signal through gap junctions
direct
___________: signaling molecules made by oxidation of fatty acids (arachidonic acid)
eicosanoids
Two major eicosanoids
1. _____________: synthesized from arachidonic acid through actions of enzymes COX
2. ____________: synthesized from arachidonic acid through actions of enzymes LOX
- Prostanoids
- Leukotrienes
Arachidonic acid is released from the plasma membrane through enzymatic action of ________________ ____. This enzyme catalyzes the hydrolysis of membrane phospholipids releasing arachidonic acid as free fatty acids
phospholipase A2
- COX=_____________ and it produces _________ from arachidonic acid
- LOX=______________ and it produces __________ from arachidonic acid
- cyclooxygenase; prostanoids
- lipoxygenases; leukotrienes
Three types of prostanoids
1.
2.
3.
- Prostaglandins (PGs)
- Prostacyclin (PGI2)
- Thromboxane (TXA2)
In the lungs and airways what do leukotrienes do?
- bronchoconstriction (narrowing of airways in the lungs)
- mucus secretion
In the GI mucosa…
- Isoenzyme of COX produced is _________ which generates _________ (______________)
The function of this prostanoid is ________ protection:
- increase ________ secretion
- increase ______________
- increase mucosal _______ flow
- COX-1; PGE2 (prostaglandin E2)
Gastric
- mucus
- bicarbonate
- blood
Two types of prostanoids produces in the kidneys
1.
2.
Functions they serve
- _________ glomerular filtration rate (GFR)
- increase ______ and _____ excretion
- Prostaglandin E2 (PGE2)
- Prostacyclin (PGI2)
- increase
- Na and water
In the cardiovascular system…
- COX isoenzyme found in the walls of blood vessels= _________ which generates _________
- COX-2; PGI2 (prostacycllin)
___________: aka thrombocytes, are small disc shaped cell fragments found in the blood. they play a crucial role in blood clotting and wound healing
- The COX enzyme that they express is _______
- platelets
- COX-1
In the vascular system PGI2 (__________) plays a role in
- _____________
- _____________
prostacyclin
- vasodilation
- inhibiting platelet aggregation
Which COX isoenzyme produces TXA2 (___________) in the platelets?
COX-1; thromboxane
Two functions of TXA2 in the cardiovascular system
- __________________
- ___________________
- vasoconstriction
- stimulate platelet aggregation (clot formation)
PGI2 and TXA2 have ________ effects in the blood vessels and platelets
- (____ vs ______) and (________ vs _________)
- their __________ is required for normal vascular homeostasis
opposite
- (vd vs. vc) and (inhibit vs. promote platelet aggregation)
- BALANCE
