Steroid Hormones

Question 1

What are steroid hormones derived from?

Answer 1

Cholesterol

Question 2

Cholesterol is cleaved to generate what 2 types of steroids?

Answer 2

Androgens and oestrogens

Question 3

How are oestrogens different from androgens?

Answer 3

Oestrogens have an aromatic ring introduced by aromatase

Question 4

What 2 classes can steroid hormones be grouped into?

Answer 4

1. Corticosteroids

2. Sex steroids / Gonadal steroids

Question 5

Within these 2 classes of steroids, what are the 5 types?

Answer 5

1. Glucocorticoids (cortisol)
2. Mineralocorticoids
3. Androgens
4. Oestrogens
5. Progestogens

Question 6

What are the 3 steroid glands that steroid hormones are produced by?

Answer 6

1. The adrenal cortex
2. Testes
3. Ovaries

Question 7

What hormones are produced by the adrenal cortex?

Answer 7

• Mainly adrenocortical hormones (glucocorticoids and mineralocorticoids)
• Small amounts of androgens and oestrogens

Question 8

What hormones are produced by the testes?

Answer 8

• Mainly androgens

- Small amounts of oestrogen

Question 9

What hormones are produced by the ovaries?

Answer 9

• Mainly oestrogens

- Small amounts of testosterone

Question 10

What are androgens?

Answer 10

Male sex hormones

Question 11

What is the principal androgen?

Answer 11

Testosterone

Question 12

What is the function of the gonadal steroids?

Answer 12

Development and maintenance of reproductive function, development of primary and secondary sex characteristics

Question 13

What are the 3 main gonadal steroids?

Answer 13

Progesterone, oestradiol, testosterone

Question 14

What is the principal oestrogen?

Answer 14

Oestradiol

Question 15

What is the principal glucocorticoid?

Answer 15

Cortisol

Question 16

What is the function of the glucocorticoids?

Answer 16

• Carbohydrate regulation
• Formation of glucose from amino acids and fatty acids
• Deposition of glycogen in liver
• Helps maintain blood pressure
• Anti-inflammatory and immunosuppressive actions

Question 17

What is the principal mineralocorticoid?

Answer 17

Aldosterone

Question 18

What is the function of the mineralocorticoids?

Answer 18

Mineral balance - balance between water and salts

Question 19

Where do mineralocorticoids mainly exert their effects?

Answer 19

Within the kidney

Question 20

Steroid hormones are lipophilic. What does this mean?

Answer 20

Can combine with / dissolve in lipids or fats

Question 21

Why are steroids able to diffuse across the cell membrane?

Answer 21

They are hydrophobic

Question 22

Why are steroids able to readily enter the cytoplasm?

Answer 22

They are lipophilic

Question 23

What happens once the steroid enters the cell?

Answer 23

It binds to an intracellular receptor either in the cytosol or the nucleus

Eventually binds to DNA

Question 24

What happens if the steroid binds to a receptor in the cytosol?

Answer 24

This hormone receptor complex then moves to the nucleus and then can bind to DNA

Question 25

What happens once the steroid hormone receptor complex binds to DNA?

Answer 25

1. Transcription - mRNA is transcribed and leaves the nucleus
2. mRNA is translated into a specific protein
3. Specific protein then carries out functions in the target cell

Question 26

How does the steroid hormone complex act as a transcription factor?

Answer 26

Turns on/off the gene

Question 27

What is a transcription factor?

Answer 27

A protein that controls the rate of transcription of genetic information from DNA to mRNA by binding to a specific DNA sequence

Question 28

What are transcription enhancers and silencers?

Answer 28

Groups of transcription factor binding sites that can turn a gene on/off in specific parts of the body