title: The effect of sodium depletion and potassium loading on cortisol induced hypertension in sheep.
abstract: Glucocorticoid induced hypertension has been regarded as independent of sodium (Na), in contrast to mineralocorticoid induced hypertension, which is Na+-dependent. These studies compare the effect of Na+ depletion and potassium (K+) loading on glucocorticoid hypertension induced by cortisol in conscious sheep. Cortisol (480 mg/d) for 5 days, in sheep on a normal chaff diet (90-140 mmol/d Na+, 200-250 mmol/d K+) increased mean arterial pressure by 18 mmHg on day 5, increased plasma Na+ concentration, reduced plasma K+ concentration, and did not change urinary Na+ excretion. Following Na+ depletion (Na+ loss 603 +/- 49 mmol), cortisol increased mean arterial pressure from 70 +/- 1 mmHg to 76 +/- 3 mmHg on day 5 (P less than 0.001) and the increase in pressure was significantly less than the increase seen on the normal diet (P less than 0.05). Plasma Na+ increased and plasma K+ decreased. Urinary Na+ and K+ excretion was unchanged. KCl loading (700-900 mmol/day) for 10 days had no effect on the maximum rise in mean arterial pressure (+18 mmHg with cortisol in K+ loaded sheep). Plasma Na+ and K+ fell, and urinary Na+ excretion increased during the infusion. These studies show that Na+ depletion, but not KCl loading, reduced cortisol induced hypertension in sheep. These data show that glucocorticoid hypertension is not independent of Na+ status.
mesh_terms: D000818:Animals; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006854:Hydrocortisone / Q000008:administration & dosage*; D006973:Hypertension / Q000139:chemically induced* / Q000503:physiopathology; D007262:Infusions, Intravenous; D011189:Potassium Chloride / Q000008:administration & dosage*; D012756:Sheep; D012964:Sodium / Q000502:physiology*
chemical_list: D011189:Potassium Chloride; D012964:Sodium; D006854:Hydrocortisone