steroid hormone biosynthesis

Question 1

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

Answer 1

zona glomerulosa
fasciculata
reticularis

Question 2

what does the glomerulosa (outside) synthesise

Answer 2

mineralocorticoids e.g. aldosterone

Question 3

what does the fasciculata synthesise (middle bit)

Answer 3

glucocorticoids e.g. cortisol

Question 4

what does the reticularis (inside) synthesise

Answer 4

androgens

Question 5

where is cholesterol found

Answer 5

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

Question 6

what lipids are used to transport cholesterol

Answer 6

apoproteins
triacylglycerols
phospholipids
inside lipoproteins

Question 7

where is cholesterol synthesised

Answer 7

liver

-smooth endoplasmic reticulum and cytosol

Question 8

what is cholesterol made from

Answer 8

acetyl CoA

Question 9

why is cholesterol found in cell membranes

Answer 9

decreases fluidity
decreases permeability to charged compounds
forms lipid rafts

Question 10

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

Answer 10

chromaffin cells

Question 11

what gene is involved in steroid synthesis

Answer 11

cytochrome p450 class
CYP gene aka mixed functional oxidases

Question 12

what cell produces testosterone

Answer 12

Leydig cell in response to LH

Question 13

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

Answer 13

Sertoli cell in response to FSH

Question 14

where are leydig and sertoli cells found

Answer 14

testicle

Question 15

where is LH and FSH made

Answer 15

pituritary gland

Question 16

what are the 5 classes of steroid hormone

Answer 16

androgens
estrogens
progestins
mineralocorticoids
glucocorticoids

Question 17

what are steroid hormones made from

Answer 17

cyclopentano perhydro phenanthrene nucleus

Question 18

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

Answer 18

thecal and granulosa cells

Question 19

where in the cell are sex steroids made

Answer 19

SER

Question 20

where in the cell are non sex steroids made

Answer 20

mitochondria

Question 21

what is the blood supply to the adrenal gland

Answer 21

capsular artery and medullary vein

Question 22

what enzyme produces pregnenolone

Answer 22

20,22 desmolase (removes side chain)

Question 23

how many carbons does cholesterol have

Answer 23

27

Question 24

how many carbons do progestins have

Answer 24

21

Question 25

how many carbons do androgens have

Answer 25

19

Question 26

how is testosterone produced in human testes

Answer 26

pregenolone
androstenediol
testosterone

Question 27

what hormones act on sertoli cells

Answer 27

testosterone and FSH

Question 28

what do Leydig cells produce

Answer 28

testosterone

Question 29

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

Answer 29

Sertoli

this can then act on the Leydig cells

Question 30

what enzyme converts androgens to oestrogens

Answer 30

aromatase

Question 31

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

Answer 31

estradiol

Question 32

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

Answer 32

progestins

Question 33

what ovarian cell contains aromatase

Answer 33

granulosa cell

not present in theca cell

Question 34

what does the theca cell produce

Answer 34

cholesterol > pregnenolone > progesterone > testosterone

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

Question 35

what does the granulosa cell produce

Answer 35

estradiol and progesterone

Question 36

what is the granulosa cell unable to do

Answer 36

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

Question 37

how is cholesterol taken to the steroidogenic cells

Answer 37

in the form of LDL

Question 38

what is the rate limiting step of creating cholesterol from aCoA

Answer 38

conversion of HMG-CoA to mevalonate via HMG CoA reductase

Question 39

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

Answer 39

estradiol