Flashcards in Cell Signaling Deck (38)
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
2. thyroid gland
3. Kidneys (EPO, renin)
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
CRH, TRH, GnRH, GRH, PRH
what do the tropic hormones target
ACTH: adrenal cortex
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
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
2. thryoid hormones
4. many neurotransmitters: norepinephrine, serotonin, acetylcholine, and dopamine.
epinephrine and norepinephrine are ___ hormones that are derived from ___ and produced in the adrenal medulla
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
3. G proteins
4. enzymes & second messengers
5. transcription factors
6. adapter proteins
what are hormone receptor classes
1. gated ion channels
2. receptor enzymes (insulin receptor; kinase)
4. adhesion (integrins)
5. steroid (change gene expression)
6. "orphan" (no direct enzyme activity but associated proteins)
what are features of G proteins
1. proteins with diff binding affinities dependent on whether GDP or GTP is bound targets can be diff enzymes
what are classes of G proteins
1. Gs: stimulates adenylate cyclase (inc prod cAMP
2. Gi: inhibits adenylate cyclase (dec cAMP levels)
3. Gq: stimulates phospholipase c (release inositol)
what are some toxins that interfere with G proteins
1. cholera: add ADP ribose instead of just the phosphate group and causes diahreea
2. pertussis: cAMP inc which causes mucous in lungs
the second messenger for adenylate cyclase is ____ which is activated by ____
the second mesenger for guanylate cyclase is ____ which is activated by
the second messenger for phospholipase c is ___ ___ or Calcium. Its activated by ____
IP3, DAG, PKC