Exam - Endocrine Regulation of Repro

Question 1

how many major types of GNRH

Answer 1

3 (1 in mammals)

Question 2

what are present in all vertebrates

Answer 2

decapeptides

Question 3

how is GnRH released

Answer 3

in a pulsatile manner in the median eminence

Question 4

how does GnRH travel

Answer 4

via portal blood system to the anterior pituitary

Question 5

what happens in the hypothalamus with GnRH

Answer 5

GnRH neurons receive info about internal and external status

Question 6

what are GnRH receptors

Answer 6

G-protein coupled receptors

Question 7

how many GnRH receptors do most species possess

Answer 7

at least 2

Question 8

what are the speculated exceptions for species that possess amount ofGnRH receptors

Answer 8

primates
rodents

Question 9

what can GnRH stimulate upon binding to receptors

Answer 9

both Gaq and Gas

Question 10

what happens in the pituitary when GnRH binds to receptor

Answer 10

leads to the synthesis and release of gonadotropins (LH and FSH)

Question 11

where else are GnRH receptors present

Answer 11

ovary
prostate
placenta

Question 12

what are glycoprotein hormones composed of

Answer 12

2 subunits:
common alpha
specific beta

Question 13

what are the 2 specific hormone subunits in glycoprotein hormones

Answer 13

LHB
FSHB

Question 14

what are LH and FSH produced by in most mammals

Answer 14

the same pituitary cells (gonadotropes)

Question 15

what are LH and FSH produced by in avian

Answer 15

different cell types

Question 16

what is differential regulation of LH and FSH based on

Answer 16

GnRH pulse frequency

Question 17

what is the limiting factor of LH and FSH

Answer 17

B SU

Question 18

what level is LH and FSH control

Answer 18

gene transcription level

Question 19

how are LH and FSH sotred

Answer 19

stored in vesicles until signal (GnRH) is received, then they are secreted

Question 20

what does the LH receptor activate

Answer 20

Gas - increases in cAMP

Question 21

what does the LH receptor bind

Answer 21

both LH and hCG

Question 22

what is hCG

Answer 22

placental source of gonadotropin

Question 23

what is the FSH receptor

Answer 23

also a G-protein coupled receptor signalling via Gas

Question 24

what are inhibin and activin

Answer 24

glycoproteins composed of 2 subunits

Question 25

what is inhibin produced by

Answer 25

Sertoli cells in males granulosa cells in females

Question 26

what does inhibin inhibit

Answer 26

FSH

Question 27

what does activin stimulate

Answer 27

FSH`

Question 28

what do inhibin and activin mainly act in conjunction with

Answer 28

GnRH

Question 29

what are gonadal (sex) steroids derived from

Answer 29

stepwise conversion of cholesterol - lipophilic with nuclear (intracellular) receptor

Question 30

what does the type of gonadal steroid depend on

Answer 30

the presence of specific enzyme substrate in the cell

Question 31

what type of steroid is estradiol-17B

Answer 31

potent

Question 32

what are sex steroid receptors

Answer 32

NHR - effect on gene expression

Question 33

what has recently been discovered about sex steroid receptors

Answer 33

non-genomic rapid effects discovered

Question 34

why do steroids have multiple target organs

Answer 34

steroids diffuse in virtually any cell of the body and receptors are widely distributed

Question 35

what receptor does testosterone use

Answer 35

the androgen receptor

Question 36

what are the 2 receptor types that estrogens have

Answer 36

ERa ERB

Question 37

what do receptors require

Answer 37

coactivators/regulatory molecule to mediate their actions on target gene promoters

Question 38

what is the main difference between ERa and ERB

Answer 38

location/presence (cell type) Era stimulates transcription ERB inhibits transcription

Question 39

what does the effect of drugs depend on

Answer 39

ability to bind and activate ERa or ERB

Question 40

what is the key link

Answer 40

kisspeptin

Question 41

when was kisspeptin discovered

Answer 41

early 1999/2000

Question 42

what was kisspeptin originally cloned as

Answer 42

an anti-metastasis agent

Question 43

what is kisspeptin's receptor

Answer 43

GPR54

Question 44

where has kisspeptin's receptor been localized

Answer 44

in the hypothalamus on GnRH neurons

Question 45

what has happened with kisspeptins over the last 25 years

Answer 45

kisspeptins have been studied in their role in regulating puberty and modulating the negative feedback of steroid in males and females

Question 46

what is the missing link

Answer 46

GnRH neurons do not express ERs but kisspeptin neurons do