2 Endocrine General Principles

Question 1

T/F hormones use endocrine, paracrine, neurocrine, and autocrine mechanisms?

Answer 1

T

Question 2

Hormones can be steroids, proteins, or __________?

Answer 2

derivatives of tyrosine

Question 3

In what 3 ways is hormone secretion regulated? (hint: long, short, and ultra-short loop together make up ONE of the 3)

Answer 3

feedback, neural, and chronotropic

Question 4

What are the 3 usual RESULTS of hormone action?

Answer 4

changes in: membrane permeability, second messengers, transcriptional events

Question 5

hormone receptors are usually high or low affinity?

Answer 5

high

Question 6

Hormones regulate what functions? (global card, don’t memorize just be familiar with)

Answer 6

• growth
• maturation
• body mass
• reproduction
• behavior
• substrate, mineral balance
• metabolism

Question 7

Dif. between endocrine and neucrocrine?

Answer 7

endo leaves from cell directly into blood, neuro leaves from an axon directly into blood

Question 8

Which hormones are tyrosine derivatives?

Answer 8

T4, epinephrine, norepinephrine, possibly others

Question 9

Which hormones are cholesterol derivatives?

Answer 9

cortisol, aldosterone, testosterone, estrogen, progesterone, possibly others

Question 10

Which hormones are peptides?

Answer 10

GH, insulin, oxytocin, possibly others

Question 11

tyrosine hormones are synthesized via?

Answer 11

enzymes in glandular cells

Question 12

tyrosine hormones are stored where?

Answer 12

vesicles, or as “large protein” (thyroglobulin)

Question 13

steroid hormones are synthesized how? (are not stored)

Answer 13

enzymatic pathways

Question 14

peptide hormones are synthesized via? stored where?

Answer 14

• prepro -> pro -> hormone

- vesicles

Question 15

Hormone receptors can be in what 3 cellular locations?

Answer 15

membrane, cytoplasm, nucleus

Question 16

Which class of hormone (steroid, peptide, tyrosin) may have spare receptors?

Answer 16

Peptide

Question 17

T/F binding of a hormone can up-or-down-regulate receptor number?

Answer 17

T

Question 18

Hormones have what 5 mechanisms of intracellular action? (global card)

Answer 18

• Membrane permeability
• G protein (3)
• Non-G-Protein (ex, tyrosine kinase)
• Transcriptional STEROIDS
• Non-Transcriptional STEROIDS

Question 19

What are the 3 G-protein mechanisms of hormone intracellular action?

Answer 19

• Adenylate cyclase (Gs, Gi)
• Calcium-Calmodulin
• Membrane phospholipids (Gq, w/ phospholipase C and phospholipase A2)

Question 20

CREB is used for what? (cyclic AMP response element binding protein)

Answer 20

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)]

Question 21

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.

Answer 21

:)

Question 22

T/F Activating adenylyl cyclase would lead to decreased DNA transcription?
T/F CREB gets phosphorylated?

Answer 22

• T. (can ALSO lead to increased DNA transcription)

- T

Question 23

Secretory activities are commonly stimulated by what molecule of the Ca-calmodulin pathway?

Answer 23

Ca bound to Calmodulin

Question 24

T/F Activating Gq (to phospholipase C) results in decreased prostaglandins?
T/F Both PKC and Ca directly act to increase/decrease enzyme activity?

Answer 24

• F. (increased)

- T.

Question 25

What 2 ways do hormone tyrosine kinases work?

Answer 25

1. Receptor ATTRACTS a tyrosine kinase to phosphorylate things
2. Receptor IS the tyrosine kinase

Question 26

What is the end goal of either type of tyrosine kinase activation?

Answer 26

Modulate gene expression

Question 27

T/F steroid receptors often directly bind DNA?

Answer 27

T. (have “binding fingers”)

Question 28

Steroid receptors are usually located in cytosol, or nucleus?

Answer 28

Both

Question 29

Once a steroid binds to its receptor, what happens to the receptor to allow it to affect DNA?

Answer 29

Hsp (heat shock protein) dissassociates

Question 30

Nontranscriptional steroids are slow-acting?

Answer 30

F. (Fast. Transcriptional ones are slow)

Question 31

A decrease in responsiveness to a hormone means what?

Answer 31

lower max hormone effect

Question 32

A decrease in sensitivity to a hormone means what?

Answer 32

higher conc. of hormone is required in order to reach the SAME given level of effect

Question 33

Diabetes has lower responsivity or sensitivity to insulin?

Answer 33

both

Question 34

Which hormones bind to carriers in blood?

Answer 34

steroid and thyroid hormones.

[must disassociate from carrier to become bio-active. The carrier proteins function as a “reserve” of hormone.]

Question 35

T/F some hormones circulate in their active form?

Answer 35

T (and others are activated by target cells)

Question 36

How does an RIA (radioimmunoassay) work?

Answer 36

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.

Question 37

Problem with RIA is?

Answer 37

Ab may bind to degraded, non-functional hormone molecules too because it recognizes the epitope

Question 38

Explain ELISA?

Answer 38

• 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

Question 39

Metabolic clearance rate is?

Answer 39

Opposite of plasma half life (how quickly something disappears from blood, higher=faster disappearing)

[Eqn: rate of disappearance/conc. of hormone per mL plasma]