Lec 3 - Control of release of APG hormones

Question 1

3 common pathways for anteriori pituitary cells

Answer 1

Ca2+
Pi
cAMP

Question 2

receptor for corticotropin reeasing hormone

Answer 2

CRH-R1
a GPCR (Gs)

Question 3

what pathway CRH-R1

Answer 3

adenylate cyclase
= cAMP= PKA
creates POMC gene product
which is processed and stored as ACTH

Question 4

what other hormone released from hypothal that potentiates ACTH release

Answer 4

ADH/vasopressin

Question 5

what receptor does vasopressin act on

Answer 5

V2

Question 6

what pathway does vasopressin trigger

Answer 6

PKA

Question 7

what hormone negatively feedbacks to reduce ACTH

Answer 7

cortisol (released from adrenal cortex)
this is the short loop feedback

Question 8

which enzymes porcess POMC

Answer 8

prohormone convertases (PCs) 1 and 2
converts to ACTH

Question 9

long loop feedback in ACTH release

Answer 9

cortisol will act on hypothalamus to reduce CRH release

Question 10

ultra short loop feedback in ACTH release

Answer 10

CRH acts on the neurons that release them
inhibit themselves

Question 11

where is the SCN

Answer 11

anterior hypothalamus

Question 12

peak cortisol release time

Answer 12

8am
most cardiovasc events happen at this time, thought to be a contributing factor

Question 13

when is ACTH release

Answer 13

little bit earlier than cortisol

Question 14

when is CRH released

Answer 14

earlier that ACTH lol

Question 15

how do the diurnal cycles govern recpetors

Answer 15

peak time of release, means peak no. receptors

Question 16

what hormone released from hypothalamus negatively inhibits GH release from somatotropes

Answer 16

somatostatin

Question 17

trophic action of GH

Answer 17

acts on liver to release IGF-1

Question 18

3 things that affect GH release

Answer 18

• sleep = increases GHRH
• Free Fatty Acids = increases somatostatin
• oestrogen = increases somatotrope sensitivity to GHRH

Question 19

difference in release of PRL compared to other horomones

Answer 19

default is to be released
must be inhibited
(no hormone from hypothal that triggers its release)

Question 20

what hormone inhibits secretion of prolactin

Answer 20

dopamine
which is reduced in pregnancy to increase prolactin

Question 21

when is TRH released normally

Answer 21

diurnal release (inccreases overnight)

Question 22

what environmental can reduce release of TRH

Answer 22

mental, phsyical, starvation, infection stresses

Question 23

what do LH and FSH control in testes

Answer 23

testosterone biosynthesis
spermatogenesis

Question 24

what do LH and FSH control in ovaries

Answer 24

oestrogen, prgesterone synthesis
menstrual cycle

Question 25

what negatively inhibits FSH LH in men

Answer 25

testosterone (also inhibits GnRH) and inhibin

Question 26

PRL role in FSH LH release in men

Answer 26

negatively inhibits hypothalamus (less GnRH) and gonadotropes (less FSH and LH)