3.3

Question 1

There are 6 hormones released from the hypothalamus: what are they?

Answer 1

GnRH, CRH, TRH, GHRH, Somatostatin, and Dopamine

Question 2

What kind of hormones are Somatostatin and Dopamine? What are the others?

(not necessarily important in this lecture…but overall)

Answer 2

Somatostatin and Dopamine are INHIBITORY hormones

All the others are RELEASING hormones…they end in RH…not that complicated

Question 3

What are the three types of hormones?

Answer 3

Protein
Steroid
Amine

Question 4

What concentration of a hormone is necessary to illicit an effect?

Answer 4

Very small…nano–>pico

Question 5

What is the role of carrier proteins in hormone transport?

Answer 5

Protect from being broken down in liver/kidneys

Question 6

What happens in the POSTERIOR pituitary?

Answer 6

Oxytocin and vasopressin (from hypothalamic neurons) are immediately released to general circulation

Question 7

Why are hormones from the hypothalamus released so that they will effect the ANTERIOR pituitary?

Answer 7

The hypothalamo-hyophyseal portal system bathes the anterior pituitary

Question 8

What is the primary form of hormone regulation?

Answer 8

Negative feedback

Question 9

Where is positive feed back seen with hormones?

Answer 9

Ovarian estrogen effects on ovulation

Question 10

Is hormone secretion constant throughout the day?

Answer 10

No…it is sinusoidal or pulsatile
There is a circadian rhythm component as well

If it is constant-ish than it is a sick system

Question 11

Where do preprohormones become prohormones? (protein hormones)

Answer 11

Preprohormones become prohormones in the RER

Question 12

Where do hormones become fully matured? How is this done? What happens afterwards? (protein hormones)

Answer 12

Hormones are matured in the Golgi apparatus by further cleaving

The Golgi packages the mature hormones into secretory granules

Question 13

Steroid hormones are synthesized from cholesterol…this is well known: where are the enzymes that form the final products?

Answer 13

Enzymes in the mitochondria and SER synthesize steroid hormones from cholesterol

Question 14

Are steroid hormones stored?

Answer 14

No…steroid hormones traverse cell membranes down their concentration gradients

Question 15

What form are most steroid hormones in in the serum? What is the form needed to act on target cells?

Answer 15

Steroid hormones are protein bound 99.9% of the time

The free hormone is able to enter cells

Question 16

What are the two categories of amine hormones discussed in this lecture? (shitty question I know, but I wanted to point out that these were AMINE hormones)

Answer 16

Catecholamines (AMINE is even in the name…)

Thyroid hormones

Question 17

Are catecholamines more similar to protein hormones or steroid hormones?

Answer 17

Catecholamines have properties similar to protein hormones

Question 18

What is a property of catecholamines that is similar to protein hormones?

Answer 18

Packaged in vesicles and released intermittently upon demand…like insulin

Question 19

Where are catecholamines produced?

Answer 19

Neurons

(this was the answer from this particular lecture…but NE/Epi often from chromaffin cells in adrenal medulla and DA is from substantia nigra and ventral tegmental area)

Question 20

Do thyroid hormones behave more like protein hormones or steroid hormones?

Answer 20

Thyroid hormones act more like steroids

Question 21

What property do thyroid hormones share with steroid hormones?

Answer 21

Thyroid hormone secretion involves diffusion down concentration gradient

Question 22

What receptors do thyroid hormones bind to?

Answer 22

Thyroid hormones bind to receptors of the nuclear receptor superfamily

Question 23

What are thyroid hormones synthesized on? Where are they matured?

Answer 23

Thyroid hormones are synthesized on a protein backbone and then processed in lysosomes

Question 24

What regulates thyroid hormone synthesis?

Answer 24

Thyroid hormone production is controlled by enzymatic activity and iodine availability

Also similar to steroid hormones, except iodine instead of cholesterol

Question 25

Hormones can kind of self regulate via negative/positive feedback, how else can hormones modify hormonal effects?

Answer 25

Down-regulate receptor signaling (decrease # of receptors or decrease receptor’s affinity for hormone)

Up-regulate receptor signaling (opposite of above)

Question 26

Protein/peptide hormones are not lipid soluble and bind to membrane receptors: what are the two most likely types of receptors? What are the effects of hormone binding?

Answer 26

Protein/peptide hormones bind to tyrosine kinase receptors or GPCR

Binding to these receptors causes a magnified secondary messenger cascade

Question 27

There are two major classes in the nuclear receptor superfamily (at least that’s what it looks like from this pwr pt.): what are they?

Answer 27

Steroid hormone receptors

RXR hormone receptors

Question 28

What ligands bind to steroid hormone receptors?

Answer 28

Estrogen 
Progesterones
Androgens
Glucocorticoids
Mineralcorticoids

Question 29

What is needed for steroid hormones to illicit a transcriptional response?

Answer 29

Hormone:receptor homodimers must form

Question 30

What ligands bind to RXR hormone receptors?

Answer 30

Thyroid hormones (receptor is T3R)
Vitamin D
Fatty acids, eicosanoids…PGs

Question 31

What is needed for RXR hormones to illicit a transcriptional response?

Answer 31

Hormone:receptor + retinoid:RXR heterodimer must form

Example: (Vitamin D:VDR):(retinoid:RXR)

Question 32

Which of the nuclear receptor superfamily receptors are important drug targets?

Answer 32

T3R (thyroid supplementation)
GR (glucocorticoid therapies)
PPAR (DMII treatment?)
VDR (Vitamin D responses)
PGR (progesterone therapy during pregnancy)

Question 33

What are the possible fates of hormones?

Answer 33

Oxidation via P450s in the liver
Urinary/biliary excretion
Cell uptake and degradation following receptor signaling