Steroids

Question 1

What are the three phases of stress?

Answer 1

1) Acute stress (alarm phase) - increased cortisol levels and this lasts for 6-48 hours
2) Resistance phase (chronic stress) - this lasts between 2 days to 1 month
3) Exhaustion phase (pathogenic stress) - this is when the stress lasts longer than 3 months

Question 2

What is prednisone?

Answer 2

A corticosteroid that is a synthetic version of natural cortisol with two slight differences in the structure.

Question 3

What is the action of glucocorticoid hormones in response to stress?

Answer 3

Glucocorticoid hormones work to prevent the overzealous rebound response to stress

Question 4

What may the side-effects of corticosteroids (e.g. prednisone) be?

Answer 4

Glaucoma, glycosuria, hypertension, osteoporosis or juvenile growth retardation in children

Question 5

What are the two different types of glucocorticoid receptor present in the body?

Answer 5

Alpha (binds steroids) and beta (doesn’t bind to steroids)

Question 6

Where are glucocorticoid receptors found?

Answer 6

In the cytoplasm and nucleus of most cells in the body

Question 7

Describe how glucocorticoids (e.g. cortisol) can exert changes by acting on nuclear receptors (genomic mechanism)

Answer 7

Can act via transactivation and transrepression:

Transactivation: glucocorticoid is often bound to cortisol binding globulin or albumin and is released prior to cellular entry, the glucocorticoid is lipophilic so enters the cell directly and binds to the cytoplasmic G protein-coupled receptor and then the glucocorticoid molecule enters the nucleus where it acts on promoter regions to alter transcription etc.

Transrepression: glucocorticoids (cortisol) can bind to the transcription factors in order to block the inflammatory responses

Question 8

Describe how glucocorticoids (e.g. cortisol) can exert changes by acting on the cytoplasmic receptors (rapid mechanism)

Answer 8

This can be facilitated by interaction of glucocorticoid with the cytoplasmic GR, plasma membrane GR or the interaction of glucocorticoid with the membranes in the cell itself.

Question 9

Name four corticosteroids and order them in terms of their potency from strongest to weakest

Answer 9

Dexamethasone, Methylprednisolone, Prednisone and hydrocortisone