LMP301 Lecture 9: Adrenal Disease Flashcards
Adrenal Diseases
Where are the adrenal glands?
On top of the kidneys
What happens to the adrenal gland during stressful situations?
enlarge
Adrenal gland is divided into…
- cortex
- medulla
The cortex of the adrenal gland is divided into…
- zona glomerulosa
- zona fasciculata
- zona reticularis
The adrenal medulla is a part of the…
SNS
Zona glomerulosa secretes….
aldosterone
zona fasciculata secretes…
- cortisol
- adrenal androgens & estrogens
zona reticularis secretes…
- cortisol
- adrenal androgens & estrogens
The adrenal medulla secretes…
- E
- NE
- Dopamine
What is the first enzyme to act on cholesterol during the biosynthesis of steroid hormones?
Cholesterol side chain cleavage hormone
What are the steroid hormones?
- aldosterone
- cortisol
- testosterone
ACTH
Signal needed for biosynthesis of steroid hormones
Enzyme cascade for aldosterone synthesis
- Cholesterol side chain cleavage hormone
- 3B-hydroxysteroid dehydrogenase
- 21 OH’ase
- 11 OH’ase
- 18 OH’ase
Enzyme cascade for cortisol synthesis
- Cholesterol side chain cleavage hormone
- 17 OH’ase
- 3B-hydroxysteroid dehydrogenase
- 21 OH’ase
- 11 OH’ase
Enzyme cascade for testosterone synthesis
- Cholesterol side chain cleavage hormone
- 17 OH’ase
- 17,20 OH’ase
- 3B-hydroxysteroid dehydrogenase
- 21 OH’ase
Which enzyme is unique to aldosterone synthesis?
18 OH’ase
Pathway of aldosterone synthesis
- Cholesterol
- Pregnenolone
- Progesterone
- Deoxycorticosterone
- Corticosterone
- Aldosterone
Pathway of cortisol synthesis
- Cholesterol
- Pregnenolone
- 17-OH pregnenolone
- 17-OH progesterone
- 11-deoxycortisol
- Cortisol
Pathway of testosterone synthesis
- Cholesterol
- Pregnenolone
- 17-OH pregnenolone
- DHEA
- Androstenedione
- Testosterone
Cortisol can affect…
metabolism of carbs, proteins, and fat
Effect of cortisol on carb metabolism
Raise blood glucose
- gluconeogenesis in liver
- reduce glucose used and stored
Effect of cortisol on protein metabolism
Break down muscle
Effect of cortisol on fat metabolism
Break down fat
What happens when glucocorticoids are present in excess?
cause central distribution of fat -> goes to face, neck, trunk
How do cortisol travel in the body?
90 - 98% is bound to proteins
- albumin
- cortisol binding globulin (CBG)
When can an increase of CBG be found?
- Pregnancy
- Estrogen treatment
How is cortisol metabolized in the body?
- Liver
2. Excreted in urine
Axis that controls cortisol secretion
Hypothalamic-pituitary-adrenaocortical axis
- Hypothalamus -> CRH
- a. pituitary -> ACTH
- adrenal cortex -> cortisol
Feedback of cortisol
Cortisol inhibits ACTH and CRH
What stimulates production of CRH?
Stress
Sleep/wake
What is too much cortisol called?
Cushing’s syndrome
Possible causes of Cushing’s syndrome
- tumour at pituitary (ACTH overproduction)
- ectopic ACTH
- adrenal gland tumour (excess cortisol)
- exogenous glucocorticoids
Ectopic ACTH
ACTH produced by cells other than the pituitary
What cells may produce ACTH, other than pituitary?
small cell carcinoma in the lung