endocrinology 2

triangular-shaped glands located on top of both kidneys

1) Mineralocorticoids 2) Glucocorticoids 3) Androgens

• Bind to the mineralocorticoid receptor (MR) in the distal convoluted tubule and collecting ducts of the nephron, the colon, and the salivary glands • Regulate salt and water balance • Promote Na+ reabsorption and K+ and H+ excretion EX) Aldosterone

• Bind to the glucocorticoid receptor (GR) expressed in different tissues such as lymphocytes, hepatocytes, and bone. • Regulate metabolism of fat, proteins, and carbohydrates EX) Cortisol

• Regulate sexual development • Dehydroepiandrosterone (DHEA)* and Androstenedione* • The adrenal medulla produces hormones called catecholamines. • Produced as a reaction to stress. • Main catecholamines: epinephrine* (adrenaline), norepinephrine, and dopamine

• Deficiency of mineralocorticoid aldosterone* (hypoaldosteronism) and glucocorticoid cortisol* • Signs/Symptoms: • Weakness • Hypotension • Hyperpigmentation of skin • Weight loss • Lab Findings: ↓ Aldosterone ↓ Na+ and Cl- ↓ Cortisol ↓ Hgb (anemia) ↑ ACTH • ACTH = adrenocorticotropic hormone • Corticotropin-releasing hormone (CRH) released from the hypothalamus stimulates secretion of ACTH from the anterior pituitary gland. • Regulates cortisol hormone levels

• Excess secretion of mineralocorticoid aldosterone from adrenal glands. • Signs/Symptoms: - Hypertension • Lab Findings: ↑ Na+ ↓ K+ ↓ Plasma renin

Excessive production of the glucocorticoid cortisol* Signs/Symptoms: • Hypertension • Moon face • Abdominal obesity • Weakness • Osteoporosis Lab Findings: • ↑ Cortisol • ↑ Aldosterone • ↑ Na+ • Diabetes mellitus

• 24-hour urinary free cortisol (UFC) • <2% of secreted cortisol appears in urine as free cortisol • Excretion of < 1380 nmol/d excludes diagnosis of Cushing syndrome • Dexamethasone suppression test • Measures the response of the adrenal glands to ACTH • Patient is given dexamethasone to suppress cortisol production and cortisol is measured • Interpretation: • Increased cortisol (no suppression) = Cushing Syndrome • Decreased cortisol (suppression) = Normal response • Salivary cortisol

• The adrenal medulla is the thin inner layer of the adrenal glands - Contain chromaffin cells • Hormones are produced in the chromaffin cells.( response to stress) • Epinephrine, norepinephrine, and dopamine • Homovanillic acid (HVA) - a metabolite of dopamine • Metanephrines and vanillylmandelic acid (VMA) - metabolites of epinephrine