Steroid hormones

Question 1

What are human steroids derived from?

Answer 1

Dietary steroids or made from acetyl-CoA in liver

Question 2

What is the most abundant steroid?

Answer 2

Cholesterol

Question 3

What do corticosteroids include?

Answer 3

Glucocorticoids and mineralocorticoids

Question 4

Where are oestrogen and progesterone made?

Answer 4

Ovary

Placenta during pregnancy

Question 5

Where is testosterone made?

Answer 5

Testes

Question 6

Describe the effect of anabolic steroids?

Answer 6

Interact with androgen receptors to increase muscle and bone synthesis

Question 7

Describe the pathway for the production of cholesterol from acetyl-CoA in the liver?

Answer 7

Question 8

How are steroids eliminated from the body?

Answer 8

Oxidation by cytochrome P450

Most significant pathway involves CYP3A4 in liver ER

Introduces -OH into steroid ring

Question 9

Describe how steroids exert their effects on target tissues?

Answer 9

Enter cells > bind internal receptors > steroid-receptor complex binds at Hormone Response Elements in DNA > gene expression altered

Question 10

Describe the function of the nuclear androgen receptor?

Answer 10

Allows male sex steroids to meidate the male phenotype

Question 11

What is cyproterone acetate?

What is it used for?

Answer 11

Synthetic steroid inhibitor of androgen receptor > blocks synthesis of mRNA for androgenic proteins

Used to treat hirsutism in females, and as part of hormone therapy for male-to-female gender change

Question 12

List the steroids released from the layers of the adrenal cortex?

List the secretion signal for each?

Answer 12

Zona reticularis: DHEA (signal is ACTH)

Zona fasiculata: cortisol (signal is ACTH)

Zona glomerulosa: aldosterone (signal is Ang II/III and ACTH)

Question 13

What is DHEA?

Describe its function?

Answer 13

Testosterone-like

Various protective effects of adrenal cortex

Weak androgen

Question 14

Which hormones have mineralocorticoid function?

Answer 14

Aldosterone

Progesterone

Deoxycortisone

Question 15

Describe how mineralocorticoids exert their effects on target tissues?

Answer 15

Bind cytosolic mineralocorticoid receptor > translocate into nucleus > alter gene expression

Question 16

Describe what happens to mineralocorticoid receptors when hormone is not bound?

Answer 16

Receptors bind heat shock proteins to prevent transcription of targeted genes

Question 17

Describe the effects of cortisol?

Answer 17

Stimulates protein breakdown to amino acids

Inhibits protein synthesis

Stimulates gluconeogenesis

Inhbits utilisation of glucose by adipose tissue

Facilitates lipolysis in adipose tissue

Stiulates appetite > weight gain

Question 18

Which hormone opposes cortisol?

Answer 18

DHEA

Question 19

How do glucocorticoids suppress immune and inflammatory responses?

Answer 19

Suppress cytokine synthesis

Question 20

What is dexamethasone?

What are its actions?

Answer 20

Potent synthetic glucocorticoid

Acts as an anti-inflammatory and immunosuppressant

Question 21

Which steroid is used in the treatment of asthma?

Describe the side effects?

How shoud it be administered and removed as treatment?

Answer 21

Prednisolone

SEs: cataracts, osteoporosis, myopathy, fragile skin, easy bruising, hair loss, hirsutism, puffy cheeks, buffalo neck, weight gain

Should progressively reduce dosage rather than stop altogether (adrenals significantly reduce steroid production when levels are high and it takes a few weeks for them to recover)

Question 22

What is leuprorelin?

What is it used for?

Answer 22

Analogue of GnRH > induces chemical castration via inhibition of FSH and LH release

Females: complete suppression of oestrogen and progesterone from ovaries

Males: complete suppression of testosterone from testes

Question 23

List the sex steroids, their secretion signals and functions?

Answer 23

Question 24

How are sex steroids transported in the body?

Answer 24

Bound to sex hormone-binding globulin (SHBG)

Question 25

Describe the menstrual cycle in terms of hormones?

Answer 25

Question 26

Describe the ovarian cycle in terms of generation of generation of hypothalamic releasing hormone, pituitary gonadotropic hormones and sex hormones?

Answer 26

Question 27

Which hormone is used in pregnancy tests?

Answer 27

Human chorionic gonadotropin (hCG)

Question 28

Where is testosterone produced?

Answer 28

Males: ore than 95% in Leydig cells in testes

Females: small quantities in ovaries and placenta

Zona reticularis of adrenal cortex produces in both sexes

Question 29

What are the releasing and inhibiting signals for testosterone?

Answer 29

Releasing: LH

Inhibiting: FSH (inhibits LH)

Question 30

Describe the role of sex steroids in prostate and breast cancer?

Answer 30

Growth of prostate and breast cancers remains dependent on sex steroids

Question 31

Describe hormonal therapy in the treatment of prostate cancer?

Answer 31

Andorgen deprivation therapy > decreases production or blocks effect of testosterone

Leuprorelin> agonist of GnRH receptors > interrupts pulsatile stimulation > inhbits LH and FSH release

Question 32

Describe hormonal therapy in the treatment of breast cancer?

Answer 32

Tamoxifen: oestrogen receptor antagonist in breast tissue

Letrozole: aromatase inhibitor

Question 33

Describe the action of anabolic steroids?

Answer 33

Act on muscle mass: increase production of actin and myosin, block effects of cortisol > decreased catabloism of muscle > decreased recovery time, increase BMR > decrease fat

Question 34

Describe the negative side effects of anabolic steroids?

Answer 34

Physical: liver damage, hypertension, jaundice, renal failure, acne

Psychiatric: delusions, jealousy, paranoia, irritability, feelings of invincibility

Men: reduced sperm count, shrinking testicles, infertility, prostate cancer, baldness

Women: baldness, facial hair growth, deep voice, menstrual cycle changes