Cortisol and Glucocorticoid Metabolism
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Questions and Answers

What is the primary function of cortisol in the body?

  • To facilitate the synthesis of proteins
  • To regulate circadian rhythm
  • To stimulate the immune system
  • To provide substrate for glucose synthesis through catabolism of lipids and proteins (correct)
  • What is the normal range of cortisol in plasma?

  • 5-25 µg/dl (correct)
  • 25-50 µg/dl
  • 1-5 µg/dl
  • 50-100 µg/dl
  • What is the primary controller of cortisol secretion?

  • Adrenal gland
  • Hypothalamus
  • Thyroid gland
  • Pituitary gland (correct)
  • What is the term used to describe excessive ACTH secretion by a pituitary tumor?

    <p>Cushing's disease</p> Signup and view all the answers

    What are the common symptoms of Cushing's syndrome?

    <p>Weight gain in the face, bone, and back of the neck, skin changes, and excess hair growth</p> Signup and view all the answers

    What is the primary cause of Addison's disease?

    <p>Autoimmune disorder</p> Signup and view all the answers

    What is the normal circadian rhythm of cortisol secretion?

    <p>Highest level between 7:00-9:00 am and lowest level between 4:00-11:00 pm</p> Signup and view all the answers

    What is the purpose of the Dexamethasone suppression test?

    <p>To diagnose Cushing's syndrome</p> Signup and view all the answers

    What is the function of Cortisol in the body?

    <p>To regulate nearly every type of organ and tissue within the body</p> Signup and view all the answers

    Which layer of the adrenal cortex produces Cortisol?

    <p>Zona reticular and zona fasciculata</p> Signup and view all the answers

    What is the function of Aldosterone in the kidney?

    <p>To increase absorption of Na in the distal tubules and facilitate secretion of K and H</p> Signup and view all the answers

    What is the normal range of 24-hour urinary Aldosterone secretion?

    <p>2-26 µg/24hrs</p> Signup and view all the answers

    What is the half-life period of Aldosterone?

    <p>20-30 minutes</p> Signup and view all the answers

    What is the main regulator of Aldosterone secretion?

    <p>Renin-angiotensin system</p> Signup and view all the answers

    What is the condition in which the adrenal gland releases too much of the hormone Aldosterone?

    <p>Conn's Syndrome</p> Signup and view all the answers

    How is Aldosterone carried in plasma?

    <p>Bound to albumin and corticosteroid binding globulin (CBG)</p> Signup and view all the answers

    What is the primary function of cortisol in the body?

    <p>To stimulate the output of glucose by the liver</p> Signup and view all the answers

    What percentage of cortisol in plasma is bound to corticosteroid binding globulin (CBG)?

    <p>90%</p> Signup and view all the answers

    What is the ratio of cortisol to corticosterol in the body?

    <p>90:10</p> Signup and view all the answers

    What is the effect of cortisol on plasma glucose levels?

    <p>It elevates plasma glucose levels</p> Signup and view all the answers

    What is the role of cortisol in the body?

    <p>It stimulates the output of glucose by the liver</p> Signup and view all the answers

    What is the effect of cortisol deficiency on glucose levels?

    <p>It decreases glucose levels</p> Signup and view all the answers

    What is the fate of cortisol in the plasma?

    <p>90% is bound to corticosteroid binding globulin (CBG)</p> Signup and view all the answers

    What is the role of glucocorticoids in the body?

    <p>They stimulate the output of glucose by the liver</p> Signup and view all the answers

    Study Notes

    Adrenal Cortex Function and Disorder

    Cortisol

    • Cortisol is catabolized to provide substrates for glucose synthesis
    • Cortisol secretion is controlled by ACTH from the pituitary and CRH from the hypothalamus
    • Plasma cortisol levels range from 5-25µg/dl, with 20-100µg/24hrs urinary excretion
    • Cortisol is metabolized mainly in the liver and secreted in the urine

    Cushing's Syndrome

    • Caused by excess cortisol production, often due to a pituitary tumor, adrenal tumor, or tumors elsewhere in the body
    • Symptoms include weight gain, skin changes, easy bruising, excess hair growth, generalized weakness, and high blood pressure
    • Cushing's disease refers specifically to excessive ACTH secretion by a pituitary tumor, which is relatively rare

    Addison's Disease

    • Caused by the failure to produce adequate cortisol levels, often due to autoimmune disorders, certain medications, sepsis, or bleeding into both adrenal glands
    • Symptoms include weight loss, fatigue, low blood pressure, and electrolyte imbalances

    Circadian Rhythm of Cortisol Secretion

    • Cortisol levels peak between 7-9 am and are lowest between 4-11 pm
    • Dexamethasone suppression test is used to diagnose suspected Cushing's syndrome

    Adrenal Histology

    • The adrenal gland is situated in the upper part of each kidney
    • The adrenal cortex is formed of three layers: zona glomerulosa, zona reticular, and zona fasciculata
    • Zona reticular and zona fasciculata produce cortisol, which regulates gluconeogenesis and has anti-inflammatory effects
    • Zona glomerulosa produces aldosterone, which helps maintain water and salt balance in the body

    Aldosterone

    • Aldosterone is synthesized in the adrenal cortex, carries in plasma bound to albumin and corticosteroid binding globulin (CBG), and is metabolized in the liver
    • Normal aldosterone secretion ranges from 2-26µg/24hrs
    • Half-life of aldosterone is 20-30 minutes

    Hyperaldosteronism (Conn's Syndrome)

    • Primary hyperaldosteronism is a rare condition caused by a non-cancerous tumor of the adrenal gland (adenoma), adrenal hyperplasia, or glucocorticoid receptor defects
    • Secondary hyperaldosteronism is often related to high blood pressure, cirrhosis of the liver, heart failure, and nephrotic syndrome
    • Symptoms include fatigue, headache, high blood pressure, paralysis, muscle weakness, and numbness
    • Laboratory findings include hypernatremia, hypokalemia, and metabolic alkalosis

    Hypoaldosteronism

    • Often occurs in Addison's disease due to destruction of the adrenal cortex by disease
    • Can also occur isolated due to adrenal gland destruction, G-layer enzyme deficiencies, or mild renal insufficiency
    • Symptoms include high serum potassium, low urinary potassium excretion (urine K < urine Na), and mild metabolic acidosis

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    Description

    This quiz covers the functions and regulation of cortisol, including its role in glucose synthesis, metabolism, and excretion, as well as disorders of cortisol secretion such as Cushing's syndrome.

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