Kidney function in mice lacking aldosterone

doi:10.1152/ajprenal.00257.2005.—To explore the effects of de-creased amounts or absence of aldosterone, we have disrupted the gene coding for aldosterone synthase (AS) in mice and investigated blood pressure and kidney function in AS/, AS/, and AS/ mice. AS/ mice have normal blood pressures and show no abnor-malities in electrolytes or kidney gene expression, but they have significantly higher than normal urine volume and lower urine osmo-lality. In contrast, the AS/ mice have low blood pressure, abnormal electrolyte homeostasis (increased plasma concentrations of K, Ca2, and Mg2 and decreased concentrations of HCO3 and Cl but no difference in the plasma Na level), and disturbances in water metabolism (higher urine output, decreased urine osmolality, and impaired urine concentrating and diluting ability). Absence of aldo-sterone in the AS/ mice induced several compensatory changes: an increased food intake-to-body weight ratio, an elevated plasma con