Steroid Hormones

Question 1

Human steroids derive from

Answer 1

dietary steroids or lanosterol made from acetyl-CoA in the liver

Question 2

Lanosterol is made

Answer 2

in the liver (multistep at ER) from Acetyl-coA

Question 3

What is the most abundant steroid?

Answer 3

Cholesterol

Question 4

Where is cholesterol found in the body?

Answer 4

free in membranes and as esters in internal forms (liver, lipoproteins, atherosclerotic plaque)

Question 5

What are the corticosteroids?

Answer 5

glucocorticoids (cortisol) and mineralocorticoids (aldosterone)

Question 6

What is the primary role of glucocorticoids?

Answer 6

Regulate metabolism and immune function

Question 7

What is the primary role of mineralocorticoids?

Answer 7

Maintain blood volume and control renal excretion of electrolytes

Question 8

What are the sex steroids?

Answer 8

Androgens, oestrogens, and progestagens

Question 9

What is the primary role of the sex steroids?

Answer 9

Produce sexual differences and support reproduction

Question 10

Where are oestrogen and progesterone primarily made?

Answer 10

In the ovary and the placenta during pregnancy

Question 11

Where is testosterone primarily made?

Answer 11

In the testes

Question 12

Testosterone is converted to

Answer 12

oestrogen; regulates supply of each in both males and females

Question 13

What is the rate-limiting step of sex steroid synthesis?

Answer 13

Conversion of cholesterol to pregnenolone (occurs in mitochondria)

Question 14

How do anabolic steroids increase muscle and bone synthesis?

Answer 14

Interacting with androgen receptors

Question 15

How do sex steroids change gene expression?

Answer 15

travel on sex-steroid-binding-globulin; free sex steroids cross the membrane and enter the nucleus where they find their receptor; receptor binds to a hormone response element and initiates transcription

Question 16

How do adrenal steroids (mineralocorticoids and glucocorticoids) change gene expression?

Answer 16

travel through membrane and find receptor in cytosol; activate receptor by knocking off a heat shock protein; the activated receptor enters the nucleus, finds its hormone response element, and initiates transcription

Question 17

Cyproterone

Answer 17

synthetic steroid inhibitor of the androgen receptor; blocks mRNA synthesis for androgenic proteins - can be used in testosterone cancers (ie prostate)

Question 18

Side chain cleaving enzyme

Answer 18

in the mitochondiron, cleaves cholesterol to pregnenolone (a progesterone precursor to steroid hormones)

Question 19

How do glucocorticoids suppress immune and inflammatory responses?

Answer 19

suppress cytokine synthesis: they bind a receptor in the nucleus that produces IkBa, the inhibitor of NF-kB that is bumped off by TNF to produce cytokines; tf production of IkBa blocks NF-kB from producing cytokines and activating the immune response

Question 20

Dexamethasone

Answer 20

potent synthetic glucocorticoid used as an anti-inflammatory and immunosuppresant

Question 21

Beclomethasone

Answer 21

analogue of dexamethasone, used as a nasal spray for allergies

Question 22

Prednisolone

Answer 22

used in severe asthma

Question 23

FSH in males

Answer 23

spermatogenesis and growth of seminiferous tubules

Question 24

FSH in females

Answer 24

production of ova, estradiol (estrogen), and development of follicles

Question 25

LH in males

Answer 25

produces testosterone

Question 26

LH in females

Answer 26

produces progesterone (promotes ovulation, supports corpus luteum)

Question 27

Leuprorelin

Answer 27

analogue of GnRH used to induce chemical castration via inhibition of FSH and LH release - in females this suppresses estrogen and progesterone production from the ovaries; in males suppression of testosterone from the testes - this is used as a treatment in breast, ovarian, and prostate cancers (causes an initial testosterone surge tf used w/cyproterone)

Question 28

What are the ‘beneficial’ effects of anabolic steroids?

Answer 28

increased production of actin and myosin, reduced recovery time from exercise, decrease fat (increased BMR)