T1 L6 Adrenal cortex - hormones and physiology Flashcards
What male sex hormones are produced by the outer adrenal cortex?
Dehydroepiandrosterone
Androstenedione
Testosterone
Oestradiol
What enzyme is contained in the outer zona glomerulosa?
18-hydroxylase enzyme
What hormone is synthesised by outer zona glomerulosa?
Aldosterone
What hormone is synthesised by middle zona fasciculata?
Cortisol
What hormone is synthesised by inner zona reticularis?
Androgens
What are steroids synthesised from?
Cholesterol from the diet or synthesised within the adrenal gland
Give an example of a glucocorticoid
Cortisol
Give an example of a mineralocorticoid
Aldosterone
When is ACTH secretion at its highest?
Early in the morning
Increased secretion during times of prolonged stress
When is ACTH secretion the lowest?
In the middle of the night
What percentage of cortisol is bound to plasma proteins?
90%
Describe the plasma proteins that cortisol is bound to
Corticosteroid binding globulin (CBG) - 75%
Albumin - 15%
Why is pregnancy associated with an increase in CBG?
It is a compensatory increase in circulating plasma cortisol concentration so the levels remain stable
What converts cortisol to inactive cortisol?
11-B-hydroxysteroid dehydrogenase contained in aldosterone sensitive tissue
How does cortisol elevate blood glucose?
Antagonises effects of insulin. on cellular uptake of glucose
Stimulates glycogenolysis
Stimulates hepatic gluconeogenesis