2 Endocrine General Principles Flashcards
T/F hormones use endocrine, paracrine, neurocrine, and autocrine mechanisms?
T
Hormones can be steroids, proteins, or __________?
derivatives of tyrosine
In what 3 ways is hormone secretion regulated? (hint: long, short, and ultra-short loop together make up ONE of the 3)
feedback, neural, and chronotropic
What are the 3 usual RESULTS of hormone action?
changes in: membrane permeability, second messengers, transcriptional events
hormone receptors are usually high or low affinity?
high
Hormones regulate what functions? (global card, don’t memorize just be familiar with)
- growth
- maturation
- body mass
- reproduction
- behavior
- substrate, mineral balance
- metabolism
Dif. between endocrine and neucrocrine?
endo leaves from cell directly into blood, neuro leaves from an axon directly into blood
Which hormones are tyrosine derivatives?
T4, epinephrine, norepinephrine, possibly others
Which hormones are cholesterol derivatives?
cortisol, aldosterone, testosterone, estrogen, progesterone, possibly others
Which hormones are peptides?
GH, insulin, oxytocin, possibly others
tyrosine hormones are synthesized via?
enzymes in glandular cells
tyrosine hormones are stored where?
vesicles, or as “large protein” (thyroglobulin)
steroid hormones are synthesized how? (are not stored)
enzymatic pathways
peptide hormones are synthesized via? stored where?
- prepro -> pro -> hormone
- vesicles
Hormone receptors can be in what 3 cellular locations?
membrane, cytoplasm, nucleus
Which class of hormone (steroid, peptide, tyrosin) may have spare receptors?
Peptide
T/F binding of a hormone can up-or-down-regulate receptor number?
T
Hormones have what 5 mechanisms of intracellular action? (global card)
- Membrane permeability
- G protein (3)
- Non-G-Protein (ex, tyrosine kinase)
- Transcriptional STEROIDS
- Non-Transcriptional STEROIDS
What are the 3 G-protein mechanisms of hormone intracellular action?
- Adenylate cyclase (Gs, Gi)
- Calcium-Calmodulin
- Membrane phospholipids (Gq, w/ phospholipase C and phospholipase A2)
CREB is used for what? (cyclic AMP response element binding protein)
Active PKA->Into nucleus->activates the CREB TF
[Once PKA is activated, PKA heads into nucleus and activates CREB (waiting in the nucleus bound to DNA), which then acts as a TF (transcription factor)]
Pg. 7,9 have the “general pathways” of hormones diagrammed, and you’d be better served to take a look at those than try to flashcard them. However, here is one card each to make sure you understand the concept of these diagrams.
:)
T/F Activating adenylyl cyclase would lead to decreased DNA transcription?
T/F CREB gets phosphorylated?
- T. (can ALSO lead to increased DNA transcription)
- T
Secretory activities are commonly stimulated by what molecule of the Ca-calmodulin pathway?
Ca bound to Calmodulin
T/F Activating Gq (to phospholipase C) results in decreased prostaglandins?
T/F Both PKC and Ca directly act to increase/decrease enzyme activity?
- F. (increased)
- T.
What 2 ways do hormone tyrosine kinases work?
- Receptor ATTRACTS a tyrosine kinase to phosphorylate things
- Receptor IS the tyrosine kinase
What is the end goal of either type of tyrosine kinase activation?
Modulate gene expression
T/F steroid receptors often directly bind DNA?
T. (have “binding fingers”)
Steroid receptors are usually located in cytosol, or nucleus?
Both
Once a steroid binds to its receptor, what happens to the receptor to allow it to affect DNA?
Hsp (heat shock protein) dissassociates
Nontranscriptional steroids are slow-acting?
F. (Fast. Transcriptional ones are slow)
A decrease in responsiveness to a hormone means what?
lower max hormone effect
A decrease in sensitivity to a hormone means what?
higher conc. of hormone is required in order to reach the SAME given level of effect
Diabetes has lower responsivity or sensitivity to insulin?
both
Which hormones bind to carriers in blood?
steroid and thyroid hormones.
[must disassociate from carrier to become bio-active. The carrier proteins function as a “reserve” of hormone.]
T/F some hormones circulate in their active form?
T (and others are activated by target cells)
How does an RIA (radioimmunoassay) work?
Incubate unkown # hormone molecules plus a KNOWN # of hormone molecules w/ a set amount of radioactive Ab. Then the proportion of your KNOWN hormone molecules that are now radioactive tells you how many UNKNOWN molecules there must also be.
Problem with RIA is?
Ab may bind to degraded, non-functional hormone molecules too because it recognizes the epitope
Explain ELISA?
- Unknown hormone # stuck to a plate.
- Put Ab (covalently linked to an enzyme) on it, wash rest of Ab away.
- Put substrate on the plate and see how quickly it is converted into a color by the enzyme
Metabolic clearance rate is?
Opposite of plasma half life (how quickly something disappears from blood, higher=faster disappearing)
[Eqn: rate of disappearance/conc. of hormone per mL plasma]