Few studies have investigated the hemodynamic mechanism whereby primary hyperaldosteronism causes hypertension. The traditional view holds that hyperaldosteronism initiates hypertension by amplifying salt-dependent increases in cardiac output (CO) by promoting increases in sodium retention and blood volume. Systemic vascular resistance (SVR) is said to increase only as a secondary consequence of the increased CO and blood pressure. Recently, we investigated the primary hemodynamic mechanism whereby hyperaldosteronism promotes salt sensitivity and initiation of salt-dependent hypertension. In unilaterally nephrectomized male Sprague-Dawley rats given infusions of aldosterone or vehicle, we found that aldosterone promoted salt sensitivity and initiation of salt-dependent hypertension by amplifying salt-induced increases in SVR while decreasing CO. In addition, we validated mathematical models of human integrative physiology, derived from Guyton's classic 1972 model - Quantitative Cardiovascular Physiology-2005 and HumMod-3.0.4. Neither model accurately predicted the usual changes in sodium balance, CO, and SVR that normally occur in response to clinically realistic increases in salt intake. These results demonstrate significant limitations with the hypotheses inherent in the Guyton models. Together these findings challenge the traditional view of the hemodynamic mechanisms that cause salt-sensitive hypertension in primary aldosteronism. Key words: Aldosterone, Blood pressure, Salt, Sodium, Rat.

• MeSH
• Aldosterone blood   metabolism   MeSH
• Hemodynamics * drug effects   MeSH
• Hyperaldosteronism * physiopathology   metabolism   MeSH
• Hypertension * physiopathology   etiology   MeSH
• Blood Pressure drug effects   physiology   MeSH
• Rats MeSH
• Sodium Chloride, Dietary * adverse effects   MeSH
• Models, Cardiovascular MeSH
• Disease Models, Animal * MeSH
• Rats, Sprague-Dawley * MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Aldosterone MeSH
• Sodium Chloride, Dietary * MeSH

• MeSH
• Urinalysis * MeSH
• Creatinine MeSH
• Humans MeSH
• Urine Specimen Collection MeSH
• Sodium, Dietary * MeSH
• Sodium MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Creatinine MeSH
• Sodium, Dietary * MeSH
• Sodium MeSH