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Flashcards in Male endocrine Deck (29):
1

2 main cell types in seminiferous tubule

1. leydig
2. sertoli

2

what does leydig cell produce and respond to

produce: T
responds to: LH

3

what does sertoli produce and respond to?

produce: and. binding homrone, inhibin, fluid, mullarian inhib. factor
responds to: FSH

4

what stimulates FSH/LH and how

GnRH in pulsatile fashion

5

what inhibits FSH/LH

T and inhibin

6

how often does GnRh pulse

every 2-3 hours

7

where does T feedback to and in what direction?

1. GnRH -ve
2. LH -ve

8

what are T levels in testes and rest of body

testes - 100-600ng/ml
body 2/5-10 ng/ml

9

what type of hormones are T and Est

steroid

10

what are all steroid hormones derived from

cholesterol

11

what is path from cholesterol to estrane and what are they converted to?

cholesterol>pregnane (progesteron)>androstane(androgens)>estrane(estrogens)

12

what is path from cholesterol to pregnenolone

cholesterol side chain cleavage enzyme

13

what is path from pregnenolone to androstendione

pronenolone(hydroxysteroi dehydrogenase)>progesterone(17a-hydroylase)>10-OH-progesterone(17,20 lyase)>androstenedione

14

path from pregnenolone to DHEA

pregnenolone(17a-hydroxylase)>17-OH-preg(17,20-lyase)> DHEA

15

of these 2 which is prominent

DHEA

16

what is product f DHEA and androstendione and how

testosterone vis 17B-hydroxysteroid dehydrogenase

17

what are 2 products of Test and via what enzyme

1. hihydrotestosterone (5a-reductase)
2. estradiol (CYP19 aromatase)

18

how are most adrogens bound

sex hormone binding globulin>albumin>free

19

when are 3 peaks of T in men

1. fetal - differentiation
2. neo-natal - ??
3. puberty on - reproduction

20

where is T located in the body and how much

95% testes
5% peripheral

21

what are 2 types of %a-reductase and where

type 1 - skin, body, scalp
type 2 - genitals + prostate

22

what causes BPH

DHT via type 2

23

what can be given as an inhibitor

finasteride - antagonist to type 2 5a-reductase

24

which is more stable DHT or T

DHT

25

how do DHT and T bind differently

DHT binds to same receptor but works on nuleas

26

what is T responsible for in terms of phenotype

1. muscle mass
2. sex drive
3. GnRH
4 spermatogenis
5. sexual differentiation
6. wolffian stimulation

27

what is DHT responsible for in terms of phenotype

1. external virilization
2. sexual maturation at puberty

28

what happens if we give continuous GnRh analogues

kills LH and FSH levels - slow precocious puberty and prostate cancer

29

what would systemic injections of T do to sperm production

drop it

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