L71: Posterior Pituitary & Hypothalamic-Pit-Liver (HPL) axis

Question 1

What negatively regulates GH?

Answer 1

IGF-1

Question 2

GH stimulates what in the liver?

Answer 2

IGF-1

Question 3

Caveat: GH stimulates IGF1 in the liver, in an ______ dependent manner

Answer 3

Insulin

Question 4

In what organs does IGF-1 mimic insulin?

Answer 4

Muscle, but not liver and adipose!

Question 5

Which of the following released from hypothalamus in pulsatile manner?
A. GnRH
B. GHRH
C. GH
D. GnRH and GHRH

Answer 5

D. GnRH and GHRH

Question 6

Where are all the places somatostatin is made?

Answer 6

SS28 - D cells in stomach/duodenum

SS14 - PVN of hypothalamus and pancreatic delta cells

Question 7

SS14 and SS28 have identical

Answer 7

amino termini

Question 8

Why does prolactinoma produce reproductive dysfunction?

Answer 8

Too much prolactin release negatively feeds back on hypothalamic GnRH release

Question 9

Sheehan’s syndrome

Answer 9

prolactin deficiency due to partial pituitary destruction (shock/blood loss)

Question 10

PVN has 2 cells types

Answer 10

Parvicellular and magnocellular

Question 11

Cell bodies making AVP are located in

Answer 11

PVN and SON

Question 12

AVP from parvocellular PVN regulate

Answer 12

mood (anxiety)/stress

Question 13

AVP from magnocellular SON and PVN regulate

Answer 13

fluid balance

Question 14

What is neurophysin?

Answer 14

a carrier protein located in the pro hormone for both AVP and OXY

Question 15

Along with OXY or AVP, what else is in the vesicle?

Answer 15

neurophysin I for OXY

neurophysin II for AVP

Question 16

What water transporter is on the apical membrane of distal tubule cell?
A. AQP2
B. AQP 3
C. AQP 4
D. AQP 3 and 4

Answer 16

A. AQP2

note that AQP3 and 4 are on the basolateral membrane!

Question 17

AVP defect in what disease?

Answer 17

Diabetes insipidus NOT MELLITUS

Question 18

OXY is released by _______ neurons located in the ____.

Answer 18

Magnocellular, PVN

Question 19

Induces skeletal muscle contractions at breast and uterus

Answer 19

OXY. Note: these are both positive control loops.

Question 20

What’s pitocin?

Answer 20

synthetic oxytocin used to induce labor. Sometimes physicians use this when they want to be home on time for dinner. Tsk tsk tsk.

Question 21

OXY binds what kind of receptor, to have what effect?

Answer 21

GPCR, increases intracellular Ca++

Question 22

GH is produced at what hypothalamus nucleus?

Answer 22

TRICK QUESTION. GHRH not GH is released at hypothalamus (Arcuate nucleus).

Question 23

What is in the GHRH pro hormone?

Answer 23

GHRH + GCTP (c-terminal peptide)

Question 24

What inhibits GHRH pulse frequency at hypothalamus, and GH and TSH release in pituitary?

Answer 24

SS from PeVN

Question 25

Bonus detail: what are Furin, PC1, and PC2?

Answer 25

endopeptidases that process somatostatin SS28 and SS14.

Question 26

Bonus detail: which SS predominates in brain?

Answer 26

SS14

Question 27

Bonus detail: which SS predominates in intestines?

Answer 27

SS28

Question 28

What is the primary anabolic goal of GH?

Answer 28

conserve protein

Question 29

Structurally, GH is in the same family of

Answer 29

prolactin

Question 30

Downstream GH target organ effects mediated through

Answer 30

IGF-1 (somatomedin)

Question 31

What’s somatomedin

Answer 31

IGF-1

Question 32

T/F: GHRH is pulsatile but not GH

Answer 32

F: both are