title: Renal potassium adaptation in the rat: role of glucocorticoids and aldosterone.
abstract: This study examines the role of adrenocortical hormones in the kaliuresis following an acute intragastric KCl load in conscious control (CK) and high potassium diet (HK) rats. Adrenalectomy, 1 day before test, reduced K+ excretion by 35% in CK and 60% in HK rats, leading to minimal differences in K excretion between CK and HK. By contrast, spironolactone inhibited K excretion by only 10%. Glucocorticoids (dexamethasone 3-10 micrograms/100 g) increased K+ excretion in adrenalectomized CK and to a greater extent in adrenalectomized HK rats. Aldosterone (3 micrograms/100 g) alone had a variable effect on urinary potassium excretion in adrenalectomized rats. A combination of dexamethasone (3 micrograms/100 g) and aldosterone (3 micrograms/100 g) in adrenalectomized rats induced potassium excretion equivalent to that in intact rats. Adrenalectomized HK rats had a greater kaliuretic response to dexamethasone and aldosterone than CK rats. These results 1) demonstrate a role for glucocorticoids in K+ excretion in HK rats and 2) illustrate the importance of the increased responsiveness to both glucocorticoids and mineralocorticoids in potassium adaptation.
mesh_terms: D000222:Adaptation, Physiological; D000311:Adrenal Glands / Q000502:physiology; D000450:Aldosterone / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D003907:Dexamethasone / Q000494:pharmacology; D004032:Diet; D004338:Drug Combinations; D005260:Female; D005938:Glucocorticoids / Q000502:physiology*; D007668:Kidney / Q000502:physiology*; D011188:Potassium / Q000502:physiology* / Q000652:urine; D051381:Rats / Q000502:physiology*; D011919:Rats, Inbred Strains
chemical_list: D004338:Drug Combinations; D005938:Glucocorticoids; D000450:Aldosterone; D003907:Dexamethasone; D011188:Potassium