BENIGN AND MALIGNANT HYPERTENSION AFTER ADRENAL ENUCLEATION IN THE RAT

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Abstract
Two experiments were conducted with unilaterally nephroadrenalectomized and contralaterally adrenal enucleated female rats. In 1, groups were given 1% saline, tap, or distilled water. The 1st rapidly developed malignant hypertension, severe arteriolar nephrosclerosis, and widespread vascular lesions. Those drinking tap or distilled water typically evinced delayed onset of benign hypertension, the former sooner, and lesions were restricted to kidney glomeruli. In the 2nd experiment animals were given 1% saline or distilled water to drink, with and without added hydrochlorothiazide. Rats given saline or water responded as in the 1st experiment. The drug prevented acute onset or malignant hypertension in rats drinking saline, which developed delayed, mild hypertension. It almost completely prevented hypertension in rats on water during the 3.5 months of study. One rat finally became mildly hypertensive and several others prehypertensive, indicating ultimate escape from anti-hypertensive effects. Widespread necrotizing vascular lesions were found in rats given saline alone, but only mild renal glomerular changes and arterial hypertrophy in either group given the drug, or animals given only water. Adrenal-regeneration hypertension is not a manifestation of increased sensitivity to salt, but is probably a response to a type of adrenal cortical dysfunction not yet clearly defined, but dependent on a distortion in the pattern of steroid secretion incident to reduced glandular blood flow.