HPA Pathway & Steriogenesis

Question 1

What does HPA acronym mean?

Answer 1

Hypothalamic Pituitary Adrenal

Question 2

Activation of HPA begins with secretion of what hormones?

Answer 2

CRH, AVP, Urocortin

Question 3

Where does secretion of CRH, AVP, and Urocortin come from?

Answer 3

Neurons within PVN

Question 4

Where is the PVN

Answer 4

Hypothalamus

Question 5

Neuropeptides are transported to where?

Answer 5

Posterior Pituitary or Portal Blood

Question 6

Within Anterior Pituitary CRH binds to what receptor?
What type of cell is this receptor on?

Answer 6

CRH-R1
Corticotroph cells

Question 7

Binding of CRH to CRH-R1 initiates conversion of _ to _ using _

Answer 7

POMC, ACTH, PC1

Question 8

Once ACTH is secreted into circulation it binds to _ receptors on _ cells in _ _

Answer 8

MC2R, Adrenal, Adrenal Cortex

Question 9

When ACTH binds to MC2R _ is triggered

Answer 9

Steriogenesis

Question 10

Steriogenesis
Involves the conversion of what into GCs?
What does this conversion involve?

Answer 10

Free Cholesterol
CYP & 11B-HSD

Question 11

What is the GC active in Mammals and Fish?
What is the GC active in Birds?

Answer 11

Cortisol
Corticosterone

Question 12

GC Physiological Response

Answer 12

Metabolism
Behaviour
Innate Immune Response
Acquired Immune Response

Question 13

GC Physiological Response - Metabolism

Answer 13

Gluconeogenesis
Deposition/Metabolism of Lipids
Muscle Protein Catabolism

Question 14

GC mediate their physiological effects using receptors, which receptors?
How?

Answer 14

High Affinity Mineralcorticoid Receptors and Low Affinity Glucocorticoid Receptors
Act as nuclear transcription factors for unique set of genes

Question 15

True or False: Expression levels of MR and GR and their ratio influence bioactivity of Glucocorticoids in different tissues

Answer 15

True

Question 16

Hepatic binding proteins also help regulate GCs, which hepatic binding proteins are they?

Answer 16

CBG and Albumin

Question 17

During non-stress states binding proteins sequester 95% of GC.
During stress what happens?
What happens if binding proteins become saturated?

Answer 17

CBG is released from storage used to bind GC
Circulating [GC] Increase

Question 18

Tissue GC are regulated by which isozymes?
What isozyme is abundant in placenta, testes, brain, kidneys?
What isozyme is abundant in brain, adipose, liver?
What do these isozymes do?

Answer 18

11B-HSD
11B-HSD2
11B-HSD1
Convert active cortisol into inactive cortisone