Disorders of the Adrenal Cortex 1.1 (based on Harrisons) Flashcards
Which three classes of corticosteroid hormones does the adrenal cortex produce?
“Glucocorticoids (e.g., cortisol), mineralocorticoids (e.g., aldosterone), and adrenal androgen precursors (e.g., dehydroepiandrosterone [DHEA]).”
Through which receptors do glucocorticoids and mineralocorticoids act?
“Specific nuclear receptors.”
What are the primary functions regulated by glucocorticoids and mineralocorticoids?
“Physiologic stress response. blood pressure and electrolyte homeostasis.”
What is the function of adrenal androgen precursors?
“They are converted in the gonads and peripheral target cells to sex steroids that act via nuclear androgen and estrogen receptors.”
What are the major causes of adrenal cortex hormone deficiency?
“Inherited glandular or enzymatic disorders. autoimmune destruction. infection. infarction. pituitary or adrenal gland destruction. surgery. or hormonal suppression.”
What is the usual cause of adrenal cortex hormone excess?
“Neoplasia leading to increased ACTH production by the pituitary or neuroendocrine cells or increased adrenal production of corticosteroids.”
What is the normal weight of each adrenal gland?
“6–11 g.”
Where are the adrenal glands located?
“Above the kidneys.”
How does blood flow through the adrenal cortex?
“From the subcapsular region through the zona glomerulosa. zona fasciculata. zona reticularis and finally to the adrenal medulla.”
Into which veins do the right and left suprarenal veins drain?
“Right suprarenal vein drains into the vena cava , left suprarenal vein drains into the left renal vein.”
At what gestational week do the adrenals separate from the gonads and kidneys?
“Around the sixth week of gestation.”
When does the adrenal cortex start producing cortisol and DHEA?
“Between the seventh and ninth week of gestation.”
Which nuclear receptors regulate adrenal steroidogenesis?
“SF1 (steroidogenic factor 1. NR5A1) and DAX1 (dosage-sensitive sex reversal gene 1 , NR5A1) and DAX1 (dosage-sensitive sex reversal gene 1, NR0B1).”
Which systems regulate glucocorticoid and mineralocorticoid synthesis?
“Glucocorticoids: Hypothalamic-pituitary-adrenal (HPA) axis. Mineralocorticoids: Renin-angiotensin-aldosterone (RAA) system.”
What stimulates the release of corticotropin-releasing hormone (CRH)?
“Endogenous or exogenous stress.”
What is the precursor molecule for ACTH?
“Proopiomelanocortin (POMC).”
Where is ACTH synthesized and what is its function?
“Synthesized in the anterior pituitary; regulates adrenal cortisol synthesis and affects mineralocorticoid and adrenal androgen synthesis.”
Which nucleus in the hypothalamus regulates the circadian rhythm of ACTH and cortisol secretion?
“Suprachiasmatic nucleus (SCN).”
What is the purpose of the dexamethasone suppression test?
“To diagnose glucocorticoid excess and differentiate causes of Cushing’s syndrome.”
How does dexamethasone affect ACTH and cortisol levels?
“Suppresses CRH and ACTH by binding glucocorticoid receptors. reducing endogenous cortisol production.”
What are the possible responses to a dexamethasone suppression test in Cushing’s syndrome?
“Suppression with high doses: ACTH-producing pituitary adenoma. No suppression: Adrenal tumor or ectopic ACTH-producing tumor.”
What test is used to assess glucocorticoid deficiency?
“ACTH stimulation test (cosyntropin test).”
What is the standard dose for the ACTH stimulation test?
“0.25 mg cosyntropin IM or IV.”
What is a normal cortisol response in an ACTH stimulation test?
“Cortisol level >15–20 μg/dL (400–550 nmol/L) after 30–60 minutes.”
