40 Questions
Which of the following is NOT a direct effect of glucocorticoids on glucose metabolism?
Increase glucose uptake in adipose tissue
What is the primary mechanism by which glucocorticoids regulate ACTH secretion?
Negative feedback mechanism
Which of the following is an indirect effect of glucocorticoids on blood pressure regulation?
Sensitization of arterioles to adrenaline
What is the primary function of mineralocorticoids in the body?
Regulation of blood pressure
Which of the following hormones is involved in the regulation of glycogen synthesis?
Glucocorticoids
What is the effect of glucocorticoids on protein metabolism?
Increase protein catabolism
Which of the following is an effect of glucocorticoids on the immune system?
Inhibition of immune response
What stimulates the secretion of aldosterone?
Increase in angiotensin II
What is the result of cortisol-induced insulin resistance in Cushing Syndrome?
Glucose intolerance
What is the effect of excess cortisol on protein metabolism?
Protein catabolism
What is the effect of cortisol on bone metabolism?
Loss of protein matrix leading to osteoporosis
What is the effect of ACTH on melanin production in Cushing Syndrome?
Increased melanin production
What is the purpose of the Dexamethasone Suppression Test in diagnosing Cushing Syndrome?
To suppress ACTH and cortisol production
What is the interpretation of a normal Overnight Dexamethasone Suppression Test?
Normal individuals suppress serum cortisol to 140 nmol/l
What is the result of excess GH on bone metabolism in Cushing Syndrome?
Bone disease
What is the effect of cortisol on collagen production in Cushing Syndrome?
Loss of collagen leading to vascular rupture
Which adrenal cortical disorder is characterized by hypersecretion of adrenal androgens?
Virilization
What is the underlying cause of Cushing Disease?
Pituitary adenoma
What is the term for chronic hypercortisolism caused by hyperfunction of the adrenal cortex or ectopic ACTH production?
Cushing syndrome
What is the result of an overproduction of ACTH by the pituitary gland?
Secondary hyperfunction of the adrenal cortex
What is the term for a condition that results from the chronic administration of glucocorticoids?
Cushing-like syndrome
Which of the following is NOT a cause of Cushing syndrome?
Hypothyroidism
What is the term for a deficiency in cortisol production?
Hypocorticolism
Which of the following is an example of a pituitary-independent cause of Cushing syndrome?
Adrenal cortex hyperfunction
What is the primary stimulus for aldosterone secretion?
Angiotensin
Which of the following is a clinical manifestation of hyperaldosteronism?
Hypokalemia
What is the term for autonomous hypersecretion of aldosterone by the adrenal gland?
Primary hyperaldosteronism
What is the expected outcome of aldosterone suppression test in secondary hyperaldosteronism?
Both renin and aldosterone levels are high
Which of the following is a cause of secondary hyperaldosteronism?
Hypovolemia
What is the expected effect of hyperaldosteronism on blood pressure?
Increased blood pressure
Which electrolyte is expected to be decreased in hyperaldosteronism?
Potassium
What is the term for a condition characterized by autonomous hypersecretion of aldosterone by the adrenal gland due to an adrenal adenoma?
Conn disease
What is the characteristic of primary hyperaldosteronism in terms of aldosterone and renin levels?
Aldosterone high, renin normal/low
What is the purpose of the Captopril Suppression Test in diagnosing hyperaldosteronism?
To determine the response of aldosterone production to angiotensin-converting enzyme inhibition
What is the effect of hypersecretion of adrenal androgens on females?
Virilization, with hirsutism, deepening voice, and amenorrhea
What is the primary treatment for androgen-secreting tumors?
Surgical removal of the tumor
What is the characteristic symptom of pheochromocytomas?
Persistent hypertension with headaches
What is the purpose of imaging techniques in the evaluation of pheochromocytomas?
To localize the tumor and determine its size
What is the effect of primary hyperaldosteronism on renin levels?
Renin levels are normal
What is the effect of hypersecretion of adrenal estrogens on males?
Feminization, with gynecomastia, testicular atrophy, and reduced libido
Study Notes
Glucocorticoids
- Increase protein catabolism
- Increase hepatic glycogen synthesis
- Increase hepatic gluconeogenesis
- Inhibit ACTH secretion (negative feedback mechanism)
- Sensitive arterioles to the action of adrenaline (involved in hemostasis of blood pressure)
- Immunosuppressive
Cortisol
- Secreted by the zona fasciculata of the adrenal cortex
- Regulates glucose, protein, and lipid metabolism
- Influences blood pressure, immune response, and inflammatory response
Adrenal Cortical Disorders
- Hypercorticolism (Cushing syndrome)
- Hypocorticolism (Addison disease)
- Hyperaldosteronism (Conn disease)
- Hypoaldosteronism (rare, potential cause of hyperkalemia)
Cushing Syndrome
- Chronic hypercortisolism due to hyperfunction of the adrenal cortex or ectopic ACTH production
- Causes:
- Pituitary-dependent hypercortisolism (Cushing disease)
- Pituitary-independent hypercortisolism (ectopic ACTH production)
- Iatrogenic disease (Cushing-like syndrome)
- Symptoms:
- Truncal obesity
- Glucose intolerance
- Muscle wasting
- Osteoporosis
- Affect GH on bone (bone disease)
- Loss of collagen (vascular rupture, bleeding problem)
- Increased ACTH (hyperpigmentation)
Biochemical Investigations for Cushing Syndrome
- Urinary free cortisol
- Serum cortisol (especially for investigation of diurnal secretion pattern)
- Serum ACTH (often high with ectopic secretion, low in primary hypercorticolism)
- Dexamethasone suppression tests (over-night, low-dose, high-dose)
Mineralocorticoid (Aldosterone)
- Regulation:
- Secreted by cells in the zona glomerulosa in response to angiotensin II and ACTH
- Clinical effects:
- Retains sodium and water
- Accompanied by potassium depletion
- Leads to excess intravascular volume and hypertension
Hyperaldosteronism
- Primary hyperaldosteronism: autonomous hypersecretion of aldosterone by the adrenal gland
- Secondary hyperaldosteronism: increase in aldosterone secretion secondary to an increase in renin
- Symptoms:
- Sodium and water retention
- Hypertension
- Hypokalemia
- Hypernatremia
- Hypervolemia
Evaluation and Treatment of Hyperaldosteronism
- Serum and urinary electrolytes
- Serum and urinary aldosterone
- Aldosterone suppression test (measure aldosterone and renin levels)
- Imaging techniques (to localize causes)
Tests for Hyperaldosteronism
- Basal level of plasma aldosterone
- Urinary aldosterone
- Captopril suppression test
- Aldosterone suppression test (isotonic saline infusion)
Hypersecretion of Adrenal Androgens and Estrogens
- Effects depend on hormone secreted, gender, and age
- Estrogen:
- Feminization (male: gynecomastia, testicular atrophy, reduced libido; female: early development of sex characteristics)
- Androgen:
- Virilization (female: hirsutism, deepening voice, amenorrhea, breast atrophy, acne)
Treatment of Hypersecretion of Adrenal Androgens and Estrogens
- Surgical removal of androgen-secreting tumors
Pheochromocytomas
- Tumors of the adrenal medulla
- Secrete excess catecholamines
- Cause persistent hypertension
- Headaches (affected cerebral blood flow)
- Many other metabolic symptoms
Evaluation and Treatment of Pheochromocytomas
- Increased catecholamine in serum and urine
- Imaging (to locate tumor)
- Treatment (surgical tumor removal)
This quiz covers the functions of glucocorticoids, specifically cortisol, including protein catabolism, hepatic glycogen synthesis, and gluconeogenesis.
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