Hormones and Receptors Flashcards
hypothalamus communicates to the
pituitary
the hypothalamus is the control system of the
endocrine system
the hypothalamus produces (3)
dopamine
ADH (vasopressin)
oxytocin releasing hormones
the pituitary is the master gland of the
endocrine system
the pituitary gland produces (6)
releasing hormones GH LH prolactin oxytocin vasopressin
the pineal gland produces
melatonin
the thyroid gland produces (3)
T3
T4
calcitonin
the parathyroid gland produces
PTH
the adrenal gland produces (2)
steroids
catecholamines
steroids (3)
androgens
glucocorticoids
mineralcorticoids
catecholamines (2)
epinephrine
norepinephrine
the kidney produces (2)
calcitriol
erythropoietin
the testis produce (2)
androgens
estradiol
the pancreas produces (2)
insulin
glucagon
bone (osteocytes) produces (2)
FGF23
sclerostin
adipose tissues produces (1)
leptin
nongenomic effects vs genomic effects
nongenomic: happen inside the cell that dont require gene expression
genomic: result in changes in gene expression
example of nongenomic effects
extranuclear rearrangement of cytoplasm
example of genomic effects
translocation of signaling molecules into the nucleus to act as a transcription factor
diffuse into the nucleus to bind to other proteins
cell-surface receptors are present in a — number
finite, recycled
the target cell expresses specific — —
receptor proteins
vmax=
the maximum concentration rate
km=
half vmax
kd=
dissociation constant
tells us if it is a high or low affinity receptor
promiscuous=
at a high concentration of ligand, it may bind to a ligand that is not their specific ligand
=low affinity binding
at very low concentrations (<10^-8 M) and their cognate receptors bind with — — (association or affinity constant at Ka>10^8 L/M) (affinity constant is the reciprocal of the dissociation constant)
high affinity
specificity of signaling molecule (hormone) action is regulated by the presence of the
receptor to which the molecule (hormone) binds
for many hormones, multiple receptor isoforms (subtypes) exist, each of which may have a specific — — that it regulates or acts through
intracellular pathway
why do we have negative feedback loops?
continuous expression of a hormone may be bad
what type of communication is hormone signaling?
cell-cell communication
what is the type of cell-cell communication defined by? (4)
where the signal originates
where the signal is released into
where the target(s) is/are located
what types of cells are involved in the signaling
juxtacrine signaling is — dependent
contact
synaptic signaling
form of paracrine, chemical synapses; or juxtacrine, electrical synapses
how are gap junctions used in cell cell communication?
small molecules can move through gap junctions
types of ligands (3)
protein and peptide hormones
catecholamines
eicosanoids
catecholamines
epinephrine (adrenaline)
norepinephrine (dopamine)
eicosanoids are derived from (2)
arachidonic acid or polyunasturated fatty acids (ex. prostoglandins)
receptors are generally designated by the — they bind, or “historic” or function based nomenclature
ligand
GPCR have - transmembrane spanning domains
7
following the binding of a hormone to its plasma membrane associated receptor, a series of intracellular events occur that lead to
ultimate changes in cell function
epinepherine stimulates glycogen breakdown in the liver by the activation of adenylate cyclase, resulting in the formation of
cAMP from ATP
cAMP then binds to the inactive form of pka causing the release of the catalytic subunits of pka that ultimately lead to the
activation of phosphorylase-alpha and breakdown of glycogen to glucose-1-phosphate
what are hydrophilic second messengers?
water soluble, located in the cytoplasm
examples of hydrophilic second messengers (4)
cAMP
cGMP
IP3
Ca2+
what are hydrophobic second messengers?
water insoluble, membrane associated and diffuse from the plasma membrane and bind to membrane associated effector proteins involved in a variety of signaling cascades
examples of hydrophobic second messengers (2)
DAG
phosphatidylinositols
examples of gases which diffuse through both cytosol and aceoss cell membranes (3)
NO
CO
HS
TSH
target tissue:
major response:
target tissue: thyroid gland
major response: thyroid hormone synthesis and secretion
ACTH
target tissue:
major response:
target tissue: adrenal cortex
major response: cortisol secretion
LH
target tissue:
major response:
target tissue: ovary
major response: progesterone secretion
adrenaline (2)
target tissue:
major response:
target tissue: muscle
major response: glycogen breakdown
target tissue: heart
major response: increase of HR and force of contraction
parathormone
target tissue:
major response:
target tissue: bone
major response: bone absorption
glucagon
target tissue:
major response:
target tissue: liver
major response: glycogen breakdown
vasopressin
target tissue:
major response:
target tissue: kidney
major response: water resorption
adrenaline, ACTH, glucagon, TSH
target tissue: fat
major response: triglyceride breakdown
what codes for the g-protein which activates adenylate cyclase?
GNAS
GNAS is expressed in (2)
endocrine glands and bone
McCune-Albright syndrome
caused by a mutation in GNAS which results in a G-protein which is always “on”. This leads to over-production of several hormones resulting in abnormal bone growth, unusual skin pigmentation, and endocrine problems. Not inherited, caused by a somatic mutation which leads to some cells expressing normal version of GNAS and some expressing the mutated version—situation called mosaicism.
McCune-Albright syndrome is NOT
inherited
mosaicism
a somatic mutation which leads to some cells expressing normal version of GNAS and some expressing the mutated version
Gs
associated with activation of adenylate cyclase
Gi
associated with inhibition of adenylate cyclase
Gp
associated with activation of phospholipase C
Gt
transducin, associated with activation of cGMP phosphdiesterase
G
possibly Go associated with receptor mediated regulation of ion channels
placental estrogens
maintenance of pregnancy
placental progestins
mimic action of progesterone
ovarian estrogens
maturation and function of female secondary sex organs
testicular androgens
maturation and function of male secondary sex organs
adrenal cortical glucocorticoids
diverse effects on inflammation and protein synthesis
adrenal mineralcorticoids
maintenance of salt balance
kidney calcitriol (biologically active vitamin D3)
maintains calcium and phosphorus homeostasis, increases calcium uptake by intestine, regulates bone mineralization
cell signaling pathways — the signal many fold in achieving a cellular response
amplify
the 3D binding specificity exhibited by hormone/receptor recognition affords scientists the opportunity to develop antagonists and agonists to
block the action of hormones
tamoxifen
antagonist of the estrogen receptor which is used to successfully inhibit growth of estrogen dependent tumors
hormone signaling pathways are the targets of (2)
genetic mutations
bacterial toxins
inactivating mutations cause disruptions in these pathways giving rise to
serious changes in the cell function
— binding bacterial toxins whose inactivating or activating effects contribute to physiological effects of diptheria, pertussis, and cholera
GTP
synthetic recreational and addictive drugs mediate their effects by interfering with
normal hormone cell signaling pathways in the brain and other tissues
ex. cocaine, meth, marijuana
