Intro to Endocrinology

Question 1

What is juxtacrine signaling?

Answer 1

Physical interaction between cells. Examples are RANK-RANKL and FAS-FASL.

Question 2

What is intacrine signaling?

Answer 2

When a molecule released by one part of the cell interacts with another part of the cell. Example is IP3

Question 3

What does dopamine do primarily?

Answer 3

Inhibits prolactin release from the AP

Question 4

A pituitary tumor that releases GH (sommatotroph tumor) will cause ________ if growth plates haven’t closed yet, and ________ if the growth plates have already closed.

Answer 4

gigantism if the growth plates have not closed

acromegaly if the growth plates have already closed

Question 5

How does GH affect glucose tolerance?

Answer 5

Excess GH causes insulin insensitivity.

Question 6

Explain how GH affects body fat homeostasis.

Answer 6

GH binds directly to adipose cells –> lipolysis.

Question 7

Explain how GH affects stature.

Answer 7

It binds to receptors on liver cells –> IGF-1.

Question 8

Name three polypeptide hormones.

Answer 8

1. Insulin
2. Glucagon
3. PTH

Question 9

Name three steroid hormones.

Answer 9

1. Cortisol
2. Estradiol
3. Cholecalciferol

Question 10

Name three AA derivative hormones.

Answer 10

1. Epinephrine
2. Norepinephrine
3. T3

Question 11

Name two lipid hormones.

Answer 11

1. Prostaglandins

2. Leukotrienes

Question 12

Name a gas hormone.

Answer 12

Nitric oxide

Question 13

What hormone has a very long half life?

Answer 13

Thyroxine (7 days)

Question 14

What hormones have very short half lives?

Answer 14

Epi and norepi (15 seconds)

Question 15

Peptide hornomes are stored in…?

Answer 15

secretory vesicles

Question 16

Are steroid hormones not stored, but synthesized from stored cholesterol?

Answer 16

Yeah

Question 17

How is hormone association equilibrium calculated?

Answer 17

[HR]/[H][R] = K1/K2 = Kassociation

Question 18

Where are T3’s cellular receptors located (intracellular or extracellular)?

Answer 18

intracellular - in the nucleus!

Question 19

By what receptor mechanism does epi and norepi illicit a cellular response?

Answer 19

Extracellular receptor binding –> signal transduction –> cAMP, Ca, cGMP, PIP3, DG –> phosphorylation

Question 20

The insulin receptor beta subunit has ______ _______ activity. Is this receptor in the plasma membrane?

Answer 20

tryosine kinase

yeah its in the plasma membrane

Question 21

Aminoglutethimide is a drug that blocks the conversion of cholesterol to pregnenolone. Administration of this drug would decrease the circulating levels of:

a) insulin
b) epinephrine
c) T3
d) cortisol

Answer 21

d) cortisol

Question 22

A hormone that acts by binding to receptors that are primarily in the nucleus is:

a) insulin
b) T3
c) glucagon
d) epinephrine
e) ACTH

Answer 22

b) T3

Question 23

The effects of GH on stature are mediated by:

a) t3
b) insulin
c) somatostatin
d) IGF-1
e) glucocorticoid

Answer 23

d) IGF-1

Question 24

Which of the following hormones have receptors that are integral tryosine kinases?

a) glucocorticoid
b) prolactin
c) GH
d) PTH
e) insulin

Answer 24

e) insulin