Adrenal Glands and Their Hormones

Adrenal Glands Overview

• Adrenal glands, also known as suprarenal glands, are located atop the kidneys and are critical for hormone release in stress response.
• Each gland consists of two main structures: the adrenal cortex and the adrenal medulla.
• The adrenal cortex produces glucocorticoids (cortisol), mineralocorticoids (aldosterone), and sex hormones (androgens).
• The adrenal medulla secretes epinephrine and norepinephrine, key players in the fight-or-flight response.

Adrenal Cortex Zones

• Composed of three zones:
  • Zona glomerulosa: produces mineralocorticoids.
  • Zona fasciculata: produces glucocorticoids.
  • Zona reticularis: produces sex hormones.

Classification of Adrenocortical Steroids

• Mineralocorticoids:

  • Promote sodium retention and potassium excretion.
  • Elevated levels can cause edema and hypertension.
  • Examples include aldosterone and deoxycorticosterone.

• Glucocorticoids:

  • Have catabolic effects on carbohydrates, fats, and proteins, also act as anti-inflammatory agents and immunosuppressants.
  • Common examples are cortisone and hydrocortisone.

• Sex Hormones:

  • Includes dehydroepiandrosterone (DHEA) and testosterone.

Synthesis and Transport of Adrenocorticoids

• Synthesis begins with cholesterol, converting to pregnenolone, which transforms into various adrenocortical steroids.
• Steroids are primarily bound to corticosteroid-binding globulin (CBG) and albumin.
• Metabolized in the liver to 17-ketosteroids, excreted via urine, serving as diagnostics for adrenal disorders.

Diseases Associated with Adrenal Disorders

• Addison’s Disease:

  • Characterized by adrenal hypofunction.
  • Symptoms include hypotension, hyperkalemia, hypoglycemia, muscle weakness, skin hyperpigmentation, and weight loss.
  • Treated with corticosteroid and sodium chloride replacement therapy, commonly using fludrocortisone.

• Cushing Syndrome:

  • Caused by adrenal hyperfunction, can be primary (adrenal defect) or secondary (overproduction of ACTH).
  • Symptoms include edema, hypertension, moon face, buffalo hump, muscle weakness, hyperglycemia, and menstrual disturbances.
  • Treatments involve surgical removal of tumors, steroidogenesis inhibitors, adrenolytic agents, and receptor antagonists.

• Adrenogenital Syndrome / Congenital Adrenal Hyperplasia (CAH):

  • Resulting from enzyme deficiencies, particularly 21-hydroxylase.
  • Leads to reduced aldosterone and corticosteroids, excessive androgen production causing masculinization in females and precocious puberty in males.
  • Treated with cortisone.

• Conn’s Syndrome (Hyperaldosteronism):

  • Excess aldosterone production causing hypokalemia and hypertension.
  • Primary is idiopathic; secondary arises from increased renin-angiotensin system activity.
  • Treated with spironolactone, an aldosterone antagonist.

Corticosteroids & Their Mechanisms

• Corticosteroids exhibit anti-inflammatory actions by:
  • Stimulating lipocortin synthesis inhibiting phospholipase A2.
  • Inhibiting interleukins (IL-1, IL-2) and TNF.
  • Enhancing macrophage migration inhibitory factor (MIF).

Therapeutic Uses of Corticosteroids

• Used for adrenal insufficiency, inflammatory conditions, organ transplantation, allergic reactions, and chemotherapy-related nausea.
• Specific conditions treated include:
  • Rheumatoid arthritis, bronchial asthma, anaphylactic shock, and collagen diseases like lupus.

Corticosteroids Side Effects

• Prolonged corticosteroid use can cause:
  • Iatrogenic Cushing’s syndrome and increased infection risk.
  • Gastrointestinal ulcers, hyperglycemia, osteoporosis, cataracts, CNS disturbances, and fluid/electrolyte imbalance.
  • Potential adrenal crisis if therapy is abruptly discontinued due to adrenal suppression.

Drug Interactions and Contraindications

• Risk of peptic ulcers when paired with NSAIDs.
• Potassium-depleting diuretics may cause severe hypokalemia.
• May increase blood sugar levels, contradicting hypoglycemic drugs.
• Caution in congestive heart failure and digitalis therapy due to fluid retention risks.

This quiz covers the functions and regulations of adrenal gland hormones, including mineralocorticoids and glucocorticoids. Students will learn to differentiate these hormones and explain their pharmacological effects, as well as assess diseases linked to adrenal disorders and the side effects of glucocorticoids.