Adrenal Gland

Question 1

What type of hormones are secreted from the adrenal cortex?

Answer 1

Steroid hormones, these act on intracellular receptors and affect the protein.

Question 2

What is the action of mineralocorticoids?

Answer 2

These are responsible for regulation of Na and K. Deficiency leads to dehydration and Excess leads to hypertension.

Question 3

What is the role of glucocorticoids?

Answer 3

These increase glucose production and breakdown of proteins. Their secretion is stimulated by ACTH

Question 4

How does excess or deficient ACTH affect glucocorticoid secretion and how does this present clinically?

Answer 4

Excess ACTH: leads to increase glucose, weight gain, cushingoid, hypertension.
Deficient ACTH: decreased glucose, nausea, weight loss, underweight.

Question 5

What can lead to increased testosterone?

Answer 5

If there is an enzyme deficiency in the adrenal cortex then this can lead to an increase of precursors which are used for androgen production. This is congenital adrenal hyperplasia.

Question 6

What is POMC?

Answer 6

This is a precursor molecule for ACTH . When broken down it also releases MSH –> pigmentation.

Question 7

What is ACTH dependent Cushings?

Answer 7

This is where the problem is with the pituitary gland or an ectopic ACTH secreting tumour. ACTH increase leads to increased cortisol. Negative feedback reduces normal pituitary function.

Question 8

What is ACTH independent Cushings?

Answer 8

This is caused by an adrenal tumour and so there is excess cortisol secretion. There is increased negative feedback as so ACTH is low.

Question 9

How can we test for corticosteroid deficiency?

Answer 9

Give synthetic ACTH in the morning and test for increased cortisol.

Question 10

What is dexamthasone?

Answer 10

This should lead to increased negative feedback of pituitary adrenal axis, thus lowering cortisol secretion. It is a useful test for excess corticosteroid secretion.

Question 11

What are the two names for the cortisol carrier in the blood?

Answer 11

Transcortin or Corticosteroid binding globulin.

Question 12

What is secreted by the adrenal medulla?

Answer 12

Adrenaline, noradrenaline and dopamine.

Question 13

State some of the effects of cortisol on metabolism.

Answer 13

Cortisol is produced in stress response:
Less amino acid uptake, less protein synthesis, increased proteolysis, increased lipolysis, decreased uptake of glucose by peripheral cells, increased gluconeogenesis and glycogenesis in the liver.

Question 14

Comment on the properties of steroid hormone receptors.

Answer 14

Steroid hormone receptors are not specific. This means that when concentrations of steroids are high they bind to receptors with low affinity but this is sufficient to be effective and can cause problems.

Question 15

What is addisons?

Answer 15

Autoimmune destruction of the adrenal cortex leading to deficiency in all hormones.

Question 16

What are the clinical signs for addisons?

Answer 16

Weightloss, anorexia, weakness. Pigmentation (increased ACTH) and postural hypertension (deficient mineralocorticoids)

Question 17

What is primary adrenal failure?

Answer 17

This is failure of the adrenal gland. There is increased ACTH due to no negative feedback.

Question 18

What can cause secondary adrenal failure?

Answer 18

Long term steroids can lead to suppression of the pituitary adrenal axis and sudden withdrawal can lead to crisis. It can also be caused by a pituitary tumour suppressing ACTH production.

Question 19

Why do patients on long term steroids require an increased dose if they are to have surgery?

Answer 19

They are unable to produce a stress response.

Question 20

What is Cushings?

Answer 20

This is where there is increased cortisol secretion. This leads to weight gain, moon face, striae, depression, menstural disturbance, thin skin, easy bruising.

Question 21

What is Nelsons syndrome?

Answer 21

This is where there is no negative feedback and so there is uncontrolled growth of the pituitary which leads to high ACTH levels and therefore pigmentation.

Question 22

How does congenital adrenal hyperplasia need to be treated at birth?

Answer 22

This can lead to neonatal salt loosing crisis and must be treated as a medical emergency with steroids.

Question 23

Name the three layers of the adrenal gland and what they secrete

Answer 23

Glomerulosa - mineralocorticoids. Fasciculata - glucocorticoids. Recticulus - androgens, glucocorticoids.