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Flashcards in Cell Signaling Deck (38)
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What does RIA do

allows the detection of tiny quantities of hormones in the bloodstream which is a landmark technique for endocrinology. Take an anitibody and radio labeled target to quanitfy how much of hormone is in sample.


what are the major endocrine glands

1. hypothalamus
2. thyroid gland
3. Kidneys (EPO, renin)
4. ovaries/testes
5. adrenals
6. pancreas


what is the hypothalamic/pituitary axis

Anterior pit conn to hypothalamus by portal vein system. Things go directly into anterior pituitary. Posterior inn by axons that originate in the hypothalamus. Direct connection to secreting things into hypothalamus.


what are the steps in sending information from the hypothalmic/anterior pituitary axis

1. Hypothalamus secretes hypothalamic releasing factors into portal system that goes directly into anterior pituitary.
2. Anterior pit responds to whichever RH that has been sent out by secreting tropic hormones into circulation.
3. Hormones produce cortisol, thyroxine or sex steroids which are all classed as steroid hormones.


what are the tropic hormones

ACTH, Thyrotropin, FSH, and LH, Somatotropin, and prolactin


what are the releasing factor hormones



what do the tropic hormones target

ACTH: adrenal cortex
Thyrotropin: thyroid
FSH and LH: ovaries and testes
Somatropion: liver, bone
Prolactin: mammary glands


what are the steps in sending info to the hypothalamic/posterior pituitary axis



what two hormones are secreted in posterior pituitary

1. Oxytocin; smooth muscle contraction generator in labor
2. Vasopressin (ADH): impt in BP regulation and water balance. Targets arterioles and kidneys


what are alternative pathways that bypass the hypothalmic pituitary axis

1. Blood glucose conc. (sensed by pancreas) causes secretion of insulin and glucagon which targets muscle, adipose and liver
2. Adrenal medulla: epinephrine secretion. Targets muscle, adipose and liver


what are the signaling molecules that bind to receptors? How are they classed

Ligands; structure


What are some examples of ligands

Peptides: proteins; have genes that encode them
amine neurotransmitter: ex is serotonin
Steroids: ex is testosterone
Eicsoanoids: derived from arachidonic acid


whats so special about steroid hormones

Can pass directly through cell membrane and can change transcription of genes directly.


what are some protein hormones

1 hypothalamic hormones
2. pituitary hormones
3. pancreatic hormones
4. Lepin, renin, ANF


what are the pancreatic hormones? where are they produced?

1. alpha cells: glucagon
2. beta cells: insulin
3. gamma cells: somatostatin

Produced in islets of langerhans


what are ex of amine hormones

1. epinephrine
2. thryoid hormones
3. histamine
4. many neurotransmitters: norepinephrine, serotonin, acetylcholine, and dopamine.


epinephrine and norepinephrine are ___ hormones that are derived from ___ and produced in the adrenal medulla

amine; tyrosine


Thyroid hormones are ____that behave like steroids to regulate BMR.They are fat soluble and act like transcription factors.

Two tyrosine put together that get iodoniated and


what are ex of steroid hormones

1. androgens and estrogens
2. adrenocortical hormones: cortisol, & aldosterone
-glucocorticoids: carb metabolism
-mineralocorticoids: blood electrolytes
3. Vitamin D
4. sex steroids: testosterone and estradiol


what is a paracrine hormone. What are 3 types of them



ultimate goal of nueroendocrine signaling is to

activate kinases to alter activity of existing proteins (rapid and transient) and activate transcription factors to alter gene expression (slow and prolonged)


What does specificity refer to

Relies on interaction bet ligand and receptor


what does amplification rely on

Relies on idea that one enzyme activating a series of enzymes to cause a profound effect on cell. (enzyme cascade)


what does desensitization refer to

Beta adrenergic receptor bbinds to epi and norepi. Its G coupled. When the hormone binds receptor G protin is activated. If signal keeps coming repeatedly end up with betta and gamma subunits which attracts BetaARK which attracts BetaARR which receptor becomes internalized and its harder to get that same kind of response.


what does integration refer to

when 2 signals have opposite effects on a metabolic characteristic. Mulitple signals at the same time. Some positive some negative. Multiple phosphorylation sites. End activity is summation of those.


Signals are meant to be ____.



what are ways to regulate protein levels and activity

1. allosteric modification
2. covalent modification
3. altered transcription rate
4. controlled degradation
5. Cellular compartmentilization inhibitors.


What isan ex controlled protein degradation

ubiquitin pathway; enzymes called ubiquitin ligases attach multiple copies of ubiquitin to lysine side chains of selected proteins. Ubiquitination targets the protein for degradation by a protein complex called the 26S proteosome which chews it up into individual aa which get hydrolyzed into ubiquitine again.


What is P53

tumor suppressor protein. Not active until there is a problem. Being made all the time.


What are major classes of signaling molecules

1. ligands
2. receptors
3. G proteins
4. enzymes & second messengers
5. transcription factors
6. adapter proteins
7. inhibitors