Exam 2 (Endocrinology)

Question 1

Describe the pathway of hydrophilic hormone production.

Answer 1

mRNA –> preprohormone (via RER) –RER transport vesicle—golgi (where signal peptide is removed)–> prohormone –enzymatic processing–> hormone + c-peptide

Question 2

What are the opportunities for control in hydrophilic hormone synthesis?

Answer 2

1. transition from RER to golgi
2. released as prohormones to be activated in plasma
3. stored as complete hormone until release

Question 3

What is the transit pathway for hydrophilic hormones?

Answer 3

ICF –> ECF –> blood

Question 4

Which type of hormone has a shorter half life?

Answer 4

hydrophilic hormones have a shorter half life

Question 5

What are the methods of disposal for hydrophilic hormones?

Answer 5

bound hormones: enzymes in blood or ICF

unbound hormones: enzymes in liver or kidney

Question 6

Describe the ß₁ isoform.

Answer 6

affinity: epinephrine = norepinephrine

heart muscle contractions

Question 7

Describe the ß₂ isoform.

Answer 7

affinity: epinephrine > norepinephrine

smooth muscle relaxation

Question 8

Describe the ß₃ isoform.

Answer 8

affinity: epinephrine < norepinephrine

lipolysis

Question 9

What is the difference between an agonist and an antagonist?

Answer 9

competing ligands; agonists elicit response; antagonists block response

Question 10

What is the function of phosphodiesterase?

Answer 10

inactivates cAMP; inhibits 2nd messenger system

Question 11

What is the function of phosphatase?

Answer 11

inactivate protein by cleaving Pi

Question 12

What are the possible pathways in a hydrophilic hormone response?

Answer 12

Rs –> Gs –> adenyl cyclase –> cAMP –> PKA –> protein

Ri –> Gi –> inactivates adenyl cyclase

Question 13

What binding protein has low specificity?

Answer 13

albumin

Question 14

What binding protein has high specificity, and for what?

Answer 14

transcortin; high affinity for glucocorticoids

Question 15

Describe the hydrophobic hormone receptor pathway.

Answer 15

1. hormone –> binding domain of receptor
2. conformational change; Zn fingers; HSP fall off
3. dimerization of receptors
4. dimer binds to hormone response element of DNA
5. transactivation complex binds
6. transcirption/translation