Abstract
High-sodium/low-potassium in the modern diet, potassium excretion, and sodium retention have all been implicated in hypertension. Objectives: This study investigated the differential effects of potassium (K⁺) supplementation on blood pressure, renal function, and oxidative stress in two experimental hypertensive rat models: L-NAME-induced (nitric oxide synthase inhibitor-induced hypertension presenting with reduced NO bioavailability, endothelial dysfunction, vasoconstriction) and DOCA-salt-induced hypertension (deoxycorticosterone acetate + salt mimics volume-dependent hypertension of hypermineralocorticoidism, low renin, high sodium retention and severe cardiac fibrosis and oxidative stress). Methods: Male Sprague Dawley rats were treated with L-NAME or DOCA-salt, with or without 0.75% KCl dietary supplementation for eight weeks. Blood pressure, vascular reactivity, serum electrolytes, renal function markers, and malondialdehyde (MDA) levels were evaluated. Results: Potassium supplementation significantly reduced (20%) mean arterial pressure and (80%) oxidative stress markers in the L-NAME model but not in the DOCA-salt model. In both hypertensive models, K⁺ reduced (15%) vascular contractile response to phenylephrine, though it did not improve acetylcholine-induced vasodilation. Notably, K⁺ supplementation improved glomerular filtration rate (eGFR), sodium-potassium ratio, and renal biomarkers (urea and creatinine) in the L-NAME model, suggesting nephroprotection. However, in the DOCA-salt group, these markers either remained unchanged or worsened. Conclusions: These findings indicate that the antihypertensive and renoprotective effects of potassium are model-specific and depend on the underlying pathophysiological mechanisms, such as nitric oxide bioavailability and mineralocorticoid sensitivity. Dietary potassium may be more effective in patients with endothelial dysfunction-dominant hypertensive subtypes compared with volume-dependent hypertension and may call for K⁺ supplementation studies to be stratified by hypertension subtype.