Steroid Hormones

Question 1

Steroid hormoenes

Answer 1

Lipophilic type of hormone

Question 2

Chemical structure

Answer 2

18-21 carbon atoms
Derived from cholesterol

Question 3

Function of cortisol

Answer 3

Maintain glucose levels

Question 4

Actions of cortisol

Answer 4

Effects on carbohydrates
Catabolic
Anti-anabolic
Diabetogenic - important in fasting

Question 5

Aldosterone

Answer 5

important in maintainence of blood pressure
Reabsorption of sodium (mainly in kidney) and re-uptake of water

Question 6

Cholesterol

Answer 6

Lipophillic substance consisting of 27 carbon atoms; 3 cyclohexane rings, one cyclopentane ring, and one short hydrocarbon side chain
Precursor for all steroid hormones
Present in the plasma membranes of cells
Incorporated in the ??

Question 7

Cholesterol is the precursor for:

Answer 7

Sex steroids (Oestrogens and androgens)
C21 steroids (glucocorticoids and minerlocorticoids)

Question 8

Main minerlocorticoid in humans

Answer 8

Aldosterone

Question 9

Main glucocorticoid in humans

Answer 9

Cortisol

Question 10

Where are steroid hormones synthesised?

Answer 10

Adrenal gland; small endocrine gland on the top of the kidney

Question 11

Three layers f adrenal gland produce different things

Answer 11

Zona glomerulosa- mineralcorticoids
Zona fasciculata - glucocorticoids
Zona reticularis - sex steroids
Medulla -catecholamines

Question 12

Cholesterol -> Aldosterone pathway

Answer 12

Cholesterol transported and bound to LDL carrier in bloodstream
Cortex had LDL receptors to bind the cholesterol
In internal cell membrane compartments:
Formation of pregnenolone from cholesterol
Formation of progesterone from pregnenolone
Formation of deoxycorticosterone from progesterone
Formation of corticosterone from deoxycorticosterone
Formation of Aldosterone from corticosterone

Question 13

*** the other pathways on slide 7

Answer 13

Incudes this -> by additional enzyme in the zonal glomerulosa

Question 14

Glucocorticoids - carbohydrate metabolism

Answer 14

Stimulates gluconeogenesis & glycogenolysis
Inhibits glucose uptake action of insulin in muscle and adipose tissue

Question 15

Glucocorticoids - protein metabolism

Answer 15

Variable effects: - Inhibitory to synthesis of some proteins, e.g. collagen
- Stimulatory to synthesis of some enzymes, e.g. for
lipolysis and gluconeogenesis
Excess causes muscle breakdown (protein degradation)

Question 16

Glucocorticoids - lipid metabolism

Answer 16

Induces lipolysis
Permissive for other lipolytic agents