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Flashcards in steroid biosynthesis Deck (33):
1

Progestins

progesteron

synthesized in adrenal glands, ovaries, testes

distributed to uterus

mediates implantation and maintenance of pregnancy

2

Glucocorticoids

cortisol cortisone, corticosterone

synthesized in adrenal glands, distributed to a large number of tissues and organs (muscle, liver)

increases blood pressure and Na uptake in kidneys

mediates response to stress by increasing protein catabolism and gluconeogenesis and reducing inflammation

3

mineralocorticoids

aldosterone
11 deoxycorticosterone

made in adrenals, distributed to kidney tubules, colon, and parotid gland, increases Na/H20 retention, K excretion and blood pressure

4

Estrogens

estradiol and estrone


made in ovaries (major), placenta, adipise tissue
distributed to primary and secondary reproductive organs
mediates feminization, estrous cycle

5

Lypophilic signal molecules

steroid hormones:

progesterone, estradiol, testosterone, cortisol, aldoesterone, vitamine D

theyroid hormone-- thyroxine

retinoids, retinol, retinoic acid

small lipophilic molecules = steroids

6

i am a peptide that activates expression of desmolase

ACTH: adrenocorticotopic hormone

secreted during stressful situation like hypoglycemia, cold, and exercise

from pituitary gland but turned on by corticotropin releasing hormone from hypothalamus

hypothalamus --> cotricotropin releasing hormone ---> pituitary ---> ACTH ----> adrenals ---> cortisol release

7

i am a peptide that increases activity of desmolase

LH

hypothalamus --> GnRH --> Pituitary --> LH ---> desmolase stimulation of activity

8

i am a peptide that actives the enzyme aromatase

FSH

promotes spermatogenesis in men
stimulates menstruation in women

9

Someone is suffering from hypertension and low cortisol

what enzyme is effected

11-beta-hydroxylase, active in both aldosterone and cortisol production pws

10

Someone is suffering from a loss of sex steroids AND cortisol

what enzyme is affected

17-alpha-hydroxylase

11

someone is suffering a defect in 3 beta hydroxysteroid dehydrogenase, which lipophilic compounds are prevented from being synthesized?

all of them EXCEPT FOR ESTRONE

12

aldosterone

promotes na/h2o retention
reduced levels = too much salt
excessive levels = conn syndrome, increased blood volume, hypertension

13

cortisol

also known as hydrocotisone

anti inflammatory and autoimmune properties

stimulates breakdown ofm uscle, gluconeogenesis and glycogen synthesis

14

Conn syndrome

elevated levels of aldosterone, increased blood volume and hypertension follow

15

Cushing syndrome

elevated levels of cortisone

increased fat on face and trunk

can be caused by tumors in the pituitary or adrenal tumors or too much administration of cortiosteroids

effects ACTH feedback system

16

glucocorticoids and immune functioning

like cortisol

inhibits immune system by inducing i-kbalpha inhibitory protein. necessary for IL-2 synthesis, so decreased clonal expansion of B lymphocytes

promotes T cell apoptosis

inhibits both humoral and adaptive branches

17

mineralcorticoids target tissues....

kidneys, colon, parotid gland

contain a receptor that has equal affinity for mineral as glucocorticoids

because they want to avoid Na/Water retention, they must metabolize cortisol further via 3-beta-hydroxysteroid dehydrogenase

18

Cortisol

has affinity for minteralcorticoid receptors 100 time ore concentral than mineralcorticoids, so target tissues further metabolize it to cortisone, a compound with a much less affinity

REAL LICORICE CAN LEAD TO HYPERTENSION BECAUSE IT INHIBITS 3-beta-HYDROXYSTEROID DEHYDROGENASE

19

Vitamin D

the effects are attributed to its

active form: calcitriol

20

Vit D2

ergocalciferol

21

Vit D3

cholcalciferol

22

where are VD3 and VD2 found?

fish, eggs, plants, vitamin d fortified foods

23

Vit D is produced

through diet or through UV rays

24

Calcitriol

active form of VD, derived from VD2 and VD3

also known as 1,25-dihydroxycholcalciferol

25

V D deficiencies related to

lung diseases, autoimmune diseases, malabsorption, cancer, infections, mental sickness

osteomalacia, rickets, bone stuff

26

cholcalciferol



cholecalciferol inactive form of VD3

derived from 7-dehydrocholesterol via UV irradiation in the skin

in intestinal cells from ergocalciferol (Vit D2)

27

7-dehydrocholesterol

produced in skin

UV rays break B ring ---> cholecalciferol

28

ergocalciferol

in intestinal cells, Vit D2 ---> cholecalciferol

29

25 hydroxylase

in liver it hydroxylates cholecalciferol D3 to 25-hydroxycholecalciferol

30

1-alpha-hydroxylase

in the kidneys this enzymes converts 25 hydroxycholecalciferol to 1,25 dihydroxycholecalciferol

31

calcitriol in the body?

stimulates intestine to absorb calcium and phosphate

increases kidney absorption, promotes calcium resorption from the bone

resulting effect is an elevation in blood Ca and phosphate levels

PTH and calcitonin are peptide signals

32

common inherited defect that leads to salt wasting, hypotension, hyperglycemia due to INCREASED PRODUCTION of cortisol.

causes virilism in women due to increased flow of intermediates into adrenal androgens

21-hydroxylase

33

11 beta hydroxylase deficiency

hypertension due to increased accumulation of 11 deoxycorticosterone