Aldosterone and its metabolism in spontaneously hypertensive rats (SHR)

The development of hypertension in spontaneously hypertensive rats (SHR) was blocked by adrenalectomy and restored with aldosterone treatment. The blood pressures of normotensive strains of rat were not affected by aldosterone. Infusions of 10 micrograms aldosterone/day into adrenalectomized (ADX)--SHR, Wistar Kyoto (WKY) and Sprague-Dawley (SD) rats completely suppressed plasma renin activity in all strains and lowered plasma potassium levels to below normal in WKY and SD rats; aldosterone treated SHR were normokalemic. In acute studies, SHR responded normally to the antinatriuretic actions of aldosterone but gave a shallower kaliuretic response compared with WKY and SD rats. The urine of ADX-SHR injected with 3H-aldosterone contained a larger proportion of polar neutral metabolites of aldosterone than WKY urine but smaller amounts of acidic and sulfate metabolites. HPLC of the neutral metabolites showed that several polar compounds were present in larger amounts in SHR urine but that unmetabolized aldosterone was less than in WKY urine.