Hormones and Receptors Flashcards
Hormones producing organs and hormones in the hypothalamus:
dopamine, ADH (vasopressin), oxytocin (releasing hormones)
Which organ is the control center of the endocrine system?
hypothalamus
Which organ is the master gland of the ES?
pituitary
Where does the hypothalamus send signals to?
pituitary
Events that happen inside the cell and don’t require immediate gene expression
nongenomic effects
what are 2 nongenomic effects:
altered metabolism
altered shape or movement
Which effect results in altered gene expression?
genomic effects
What type of proteins are cell-surface receptors?
transmembrane spanning proteins
Extracellular signaling molecules act at very (high/low) concentrations
low
extracellular signaling molecules’ cognate receptors bind with (high/low) affinity at low concentrations
high
How is the specificity of the signaling molecule (hormone) action regualted?
presence of the receptor to which the molecule (hormone) binds
nomenclature of extracellular signaling molecules (8)
peptide hormones, steroid hormones, growth factors, mitogens, cytokines, neurotransmitters and chemokines
Hormone secretion:
external signal/condition triggers HYPOTHALAMUS to release RELEASING HORMONE which triggers the ANT. PIT. to release a TROPIC HORMONE which targets ENDOCRINE gland which produces HORMONE
As hormone levels increase they can FEEDBACK to the levels of the ____ and _____.
hypothalamus
pituitary
What happens if the long NEGATIVE FEEDBACK LOOPS stops working?
continuous production of hormones
Where do the short-loop negative feedback loops feedback from and to? What does it inhibt?
from TROPIC HORMONE
to HYPOTHALAMUS
inhibits releasing hormone
Hormone signaling is a type of _____ communcation.
cell-cell
How is the type of cell-cell communication defined?
- where signal ORIGINATES
- where the is RELEASED into
- where target(s) is/are located
- types of cells involved in signaling
what are the 4 mechanisms of ligand presentation to target cells
- contact-dependent (juxtacrine)
- paracrine
- synaptic
- endocrine
mechanism when one cell presents ligand to another cell nearby that has the receptor
contact-dependent (juxtacrine)
mechanism in which signaling cell produces a factor that stays within the local environment
paracrine
mechanism that is a form of paracrine signaling involving chemical synapses or juxtacrine involving electrical synapses
(neuron, NT)
synaptic
mechanism where endocrine cell produces hormone that enter bloodstream, circulates throughout the body, and initiates cellular response where it finds target cell with receptor
endocrine
What type of communication is involved in gap junctions?
cell-cell comm.
(small molecules can move through gap junctions between 2 adjacent cells
What type of signaling is stimulated by binding of hormone and produces an extracellular signaling molecule which feedbacks on cell that produced it to stimulate it.
autocrine signaling
Plasma membrane receptor systems: ligands (3)
- protein and peptide hormones
- catecholamines (epinephrine-adrenaline; norepinephrine- dopamine)
- Eicosanoids (derived from arachidonic acid or polyunsaturated fatty acids. e.g. prostaglandins)
T/F: receptors are generally designated by the ligand they bind or their function
true
receptor that has at least 7 transmembrane spanning domains and an extracellular ligand binding site
G-protein coupled receptor
What occurs following the binding of a hormone to its plasma membrane associated receptor?
series of intracellular events occur that lead to the ultimate changes in cell FUNCTION
What stimulates the G-coupled receptor in the formation of cAMP?
epinephrine
Activation of adenylyl cylase results in formation of ___ from ____.
cAMP from ATP
What does cAMP bind to and activate?
PKA
What happens after cAMP activates PKA?
activation of phosphorylase-alpha and breakdown of glycogen to glucose-1-phosphate
What are the most common intracellular second messengers?
cAMP**
cGMP
DAG
IP3
What are the 3 types of second messengers?
- hydrophilic
- hydrophobic
- gases
Where are hydrophilic 2nd messengers located and give examples of some.
cytoplasm (water-soluble)
cAMP, cGMP, IP3, Ca+2
Where are hydrophobic 2nd messengers located and give examples of some.
membrane associated
(water insoluble)
-diffuse from PM and bind to membrane associated effector proteins involved in variety of signaling cascades
-DAG and phosphoinositols
Where do 2nd messenger gases diffuse through?
both cytosol and across CM
NO, CO, HS
syndrome caused by the mutation in GNAS which results in a G-protein which is ALWAYS ON leading to overproduction of hormones resulting in abnormal bone growth, unusually skin pigmentation, and endocrine problems.
McCune-Albright syndrome
GNAS codes for the _____ which activates adenylate cycle
G-protein
Where is GNAS expressed?
endocrine glands and bone
Are somatic mutations inheritable?
no
Are mutations in G-proteins (inherited?
no - somatic
when some cells express normal version of GNAS and some express mutated version:
mosaicism
What are GTP-binding proteins inactivated by?
bacterial toxins
What is the most important class of intracellular signaling hormones?
steroid hormones
When a cell with Notch is cleaved and binds to another delta cell (juxtacrine signaling) and leads to transcription of notch target genes
signaling mediated through regulated PROTEOLYSIS
Cell signaling pathways __ initial signal many fold to achieve cellular response.
amplify
Enzyme linked cell surface receptors have ______ and _______ domains that can take on various configurations and have enzyme/kinase associated activity, respectively.
Extracellular
Intracellular
