Adrenal cortex Flashcards
Which zone is responsible for synthesising mineralcorticoids
Zona glomerulosa
Name a mineralcorticoid
Aldosterone
The zona fasciculata synthesises what?
Glucocortoids (cortisol)
What does the zona reticularis synthesis?
Androgens
What is the precursor of steroid hormones?
Cholesterol
The synthesis of sex hormones stops at which point in the adrenal cortex?
Stops at androgen. Then in gonads the androgen is converted to estrogen and testosterone
11 Beta hydroxylase catalyses which reaction?
Cortisone / deoxycortisol into hydrocortisone
Where is CRH released from and where does it act on?
Released from hypothalamus and acts on anterior pituitary
What is CRH
Corticotrophin releasing hormone
When CRH acts on the anterior pituitary, what happens?
Adrenocorticotrophic hormone(ACTH) is released
Where does ACTH bind to and what effect does it have?
Binds to adrenal cortex to stimulate the production of cortisol.
How does ACTH regulate cortisol synthesis?
The conversion of cholesterol into pregnenolone is controlled by ACTH which is the first step in the synthesis pathway.
It does this by changing the gene expression of the enzyme in the cortex that catalyses this reaction
ACTH has no effect on which region of the adrenal cortex?
Zona glomerulosa
true or false, ACTH has no effect on cholesterol update and synthesis?
False. ACTH increases cholesterol uptake and synthesis
What is the enzyme that converts cholesterol into pregnenolone?
Cholesterolesterase
What impact does ACTH have on the cells of the adrenal cortex?
Because it is a trophic hormone, it increases the size and functionality and number of the cells. No ACTH = atrophy of adrenal gland
Why is there a large surge of cortisol upon waking the morning?
Helps to mobilise your nutrients to use for energy after fasting for so long during sleep
Is cortisol anabolic or catabolic?
Catabolic. Needs to breakdown muscle and fat to release protein (amino acids) into circulation
Why is it so important to stabilise glucose levels during times of stress?
To fuel the brain, since it cannot store its own glycogen.
List 2 potential causes of Cushing’s syndrome
ACTH secreting tumour
Adrenal tumour
Over medication of anti-inflammatory steroids