steroid hormone biosynthesis Flashcards Preview

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Flashcards in steroid hormone biosynthesis Deck (39):
1

what are the 3 regions of the cortex from outside to inside

zona glomerulosa
fasciculata
reticularis

2

what does the glomerulosa (outside) synthesise

mineralocorticoids e.g. aldosterone

3

what does the fasciculata synthesise (middle bit)

glucocorticoids e.g. cortisol

4

what does the reticularis (inside) synthesise

androgens

5

where is cholesterol found

membrane lipids in order to regulate fluidity

in plasma

in cystosolic lipid droplets as cholesterol esters, mainly in steroid secreting endocrine cells

bile salts

precursor for steroid hormones

6

what lipids are used to transport cholesterol

apoproteins
triacylglycerols
phospholipids
inside lipoproteins

7

where is cholesterol synthesised

liver
-smooth endoplasmic reticulum and cytosol

8

what is cholesterol made from

acetyl CoA

9

why is cholesterol found in cell membranes

decreases fluidity
decreases permeability to charged compounds
forms lipid rafts

10

what is the name of the cells that produce epinephrine and norepinephrine

chromaffin cells

11

what gene is involved in steroid synthesis

cytochrome p450 class
CYP gene aka mixed functional oxidases

12

what cell produces testosterone

Leydig cell in response to LH

13

what cell produces estradiol, growth factors, androgen binding proteins, etc

Sertoli cell in response to FSH

14

where are leydig and sertoli cells found

testicle

15

where is LH and FSH made

pituritary gland

16

what are the 5 classes of steroid hormone

androgens
estrogens
progestins
mineralocorticoids
glucocorticoids

17

what are steroid hormones made from

cyclopentano perhydro phenanthrene nucleus

18

what cells are found in the ovary and are responsible for oestrogen and progestin production

thecal and granulosa cells

19

where in the cell are sex steroids made

SER

20

where in the cell are non sex steroids made

mitochondria

21

what is the blood supply to the adrenal gland

capsular artery and medullary vein

22

what enzyme produces pregnenolone

20,22 desmolase (removes side chain)

23

how many carbons does cholesterol have

27

24

how many carbons do progestins have

21

25

how many carbons do androgens have

19

26

how is testosterone produced in human testes

pregenolone
androstenediol
testosterone

27

what hormones act on sertoli cells

testosterone and FSH

28

what do Leydig cells produce

testosterone

29

what cell in the testes converts testosterone to estradiol in the presence of aromatase

Sertoli
this can then act on the Leydig cells

30

what enzyme converts androgens to oestrogens

aromatase

31

what is the main product of the follicle during the follicular phase

estradiol

32

what is the main product of the corpus luteum during the luteal phase

progestins

33

what ovarian cell contains aromatase

granulosa cell
(not present in theca cell)

34

what does the theca cell produce

cholesterol > pregnenolone > progesterone > testosterone

testosterone then goes to the granulosa cell and is converted to estradiol

35

what does the granulosa cell produce

estradiol and progesterone

36

what is the granulosa cell unable to do

convert progesterone to androstenedione, must send it to the theca cell

37

how is cholesterol taken to the steroidogenic cells

in the form of LDL

38

what is the rate limiting step of creating cholesterol from aCoA

conversion of HMG-CoA to mevalonate via HMG CoA reductase

39

what is the main product of the follicle during the follicular phase

estradiol