Steroid chemistry

Question 1

Basic info about steroid structure?

Answer 1

They are small organic molecules with a rigid structure. A small structural difference can result in massive differences in biological activity

Question 2

Give examples of endogenous steroids

Answer 2

• sex hormones
• corticosteroids
• steroid lipids

Question 3

Steroids are important for what?

Answer 3

They are essential structure components in cell membranes:
mammals - cholesterol
plants - beta-sitosterol
fungi - Ergosterol

Question 4

Corticosteroids are hormones released from _____ _____. There are two types:

Answer 4

mineralocorticoids

glucocorticoids

Question 5

What are the female and male sex hormones? Give examples

Answer 5

FEMALES: progestogen e.g. progesterone, oestrogen e.g. estrone, estradiol and estriol
MALES: androgens e.g. testosterone

Question 6

Why is it beneficial if we establish a SAR (structure activity relationship) for a particular activity?

Answer 6

So that we can:

• design new drugs with improved properties
• predict the activity for a known structure

Question 7

What groups added to a parent nucleus will provide additional functionality?

Answer 7

• alkene/alkyl
• hydroxy
• aldehyde
• ketone
• methyl
• halogen

Question 8

What is the most important corticosteroid?

Answer 8

Aldosterone

Question 9

What does aldosterone control?

Answer 9

Homeostasis of blood electrolyte levels and blood volume.

Question 10

What is aldosterone a major component of?

Answer 10

The renin angiotensin system

Question 11

What kinda of steroid is cortisol?

Answer 11

Glucocorticoid

Question 12

What is cortisol involved in?

Answer 12

• stress response
• inflammatory response
• protein, carbohydrate and lipid metabolism

Question 13

Substituents above the plane of a steroid are described as? How are they drawn?

Answer 13

beta 
solid line (or wedge)

Question 14

Substituents below the plane of a steroid are described as? How are they drawn?

Answer 14

alpha
broken line (or broken wedge)

Question 15

Which is the most potent steroid?

Answer 15

Betamethasone

Question 16

Which is the least potent steroid?

Answer 16

Hydrocortisone

Question 17

The weaker the potency, the ______ lower the half life

Answer 17

slower

Question 18

What are the structure requirements for corticosteroid activity?

Answer 18

• A pregnane steroid nucleus
• A hydroxyl functional group at position 11β
• An a-β unsaturated ketone at position 3; i.e double bond at 4-5
• A ketone functional group at position 20

Question 19

What is oestrogen?

Answer 19

a primary female sex hormone

Question 20

What is the role of oestrogen

Answer 20

• regulates menstruation cycle

- promotes development of secondary sex characteristics

Question 21

Name a non-steroidal oestrogen

Answer 21

Stilboestrol (DES)

Question 22

What was DES (stilboestrol) used for back n 1950s?

Answer 22

Prophylactic treatment to prevent miscarriage in first trimester

Question 23

Why was DES discontinued?

Answer 23

Daughters at increased risk of clear cell adenocarcinoma of vagina and cervix, post puberty

Question 24

What is Tamoxifen?

Answer 24

Oestrogen receptor antagonist in breast tissue. Has agonist actions in liver, bones and CV system.

Question 25

Progesterone is critical for maintenance of _______, but also has activity in maintaining the ______

Answer 25

pregnancy

uterus

Question 26

what does the prefix ‘nor’ indicate?

Answer 26

removal of methylene group.

Question 27

What sex is testosterone found in?

Answer 27

male AND female

Question 28

What is testosterone responsible for?

Answer 28

• anabolic activity

- promoting male sex characteristics

Question 29

Introduction of unsaturation into ring makes it more or less planar?

Answer 29

more