Adrenal Gland Endocrine Flashcards
Origin of Cortical cells
Medoderm -coelomic epithelium
Origin of medullary cells
Neuroectoderm
Corticosteroids
Mineralocorticoids –Aldosterone
Glucocorticoids –Cortisol
Effect of insufficient aldosterone?
Addison’s
- Decreased Na
- Increased K
Where does Aldosterone act?
Distal Renal tubules to promote reabsorption of Na and excretion of K
-regulated mainly by RAAS system
Disturbance of growth of adrenal gland
- Damage to hypothalamus/pitutiary –> disruption of fetal adrenocortical function
- Atrophy
- Hyperplasia
- Neoplasia
Causes of Cortical atrophy
- secondary to loss of pituitary corticotrophs
- Iatrogenic –long-term glucocorticoids
- Immune-mediated destruction of cortical cells
Canine idiopathic adrenocortical atrophy (Clinical signs/ Dx/ Tx)
- E-lyte imbalances
- Dx: ACTH stimulation Test
- Tx: Mineralocorticoids and Glucocorticoids replacement
Laminar hyperplasia vs Nodular hyperlasia
Laminar hyperplasia
- diffuse thickening of ZF and ZR
Nodular hyperplasia
-typically multiple nodules
Causes of hyperadrenocorticism
- Functional cortical adenoma
- Functional adrenocortical tumor
- Iatrogenic
Disorders of adrenal medulla
- Hyperplasia
2. Pheochromocytoma –more common
What is the enzyme used to convert Norepi to Epi?
Phenylethanolamine N-methyltransferase
Tyrosine –> DOPA–> dopamine–> NEpi –> epi
2 inflammatory disorders of the adrenal gland
- Immune-mediated adrenalitis
2. Systemic infection
Lesion associated with immune-mediated adrenalitis
- Lympho-plasmacytic inflammation
- Destroys all 3 layers of the cortex
- Medulla untouched
Vascular disturbances associated with the adrenal gland
- DIC –Medulla is common site for fibrin deposits
- Embolization
- Hemorrhage –common with sepsis (endotoxic shock)
- Infarct
Why is it important for fetus to have an in tact HPA axis?
- Maturation of fetal adrenal gland
2. onset of parturition
Hyperplasia/hypertrophy of adrenocortical cells (dogs)
Common lesion on old dogs
- Cushing’s dz –> excess cortisol
- common cause: Functional Corticotroph adenoma
- -> unregulated ACTH
- Dogs w/o pituitary lesions –increase hypothalamic metabolism of dopamine –> disrupt negative feedback on HPA axis
Most common hormone secreted functional adrenocortical adenomas (species)
Dog: Cortisol
Cat: Aldosterone
Ferrets: Estrogen
What species develops adrenal gland carcinoma more often?
Cattle & dogs
Pheochromocytomas
- diffuse or nodulaire medullary neoplasias
- functional –> Norepi –> systemic hypertension
