The relationship between plasma potassium concentration and the renin-angiotensin-aldosterone system was evaluated in ten patients with chronic renal failure (creatinine clearance 10–56 ml/min). Under basal conditions and following various stimulation maneuvers, normokalemic patients demonstrated normal plasma renin and aldosterone levels. Five of six patients with hyperkalemia had diminished function of the renin-angiotensin-aldosterone system; their ability to conserve sodium during salt depletion was less than that of normokalemic patients. The data suggest that the maintenance of plasma potassium levels in these patients is dependent on the presence of a normally functioning renin-angiotensin-aldosterone system; aldosterone activity may be an important determinant of sodium conservation in patients with renal failure.

A case of isolated hypoaldosteronism associated with chronic renal failure is reported. Potassium retention and hyperkalemia, sodium wasting, and inability to acidify the urine were all corrected by mineralocorticoid administration. Aldosterone secretion was 86.0 µg/day on a high sodium intake, 30.1 µg/day on a low sodium intake, and 36.2 µg/day after an angiotensin infusion. An important physiologic role is postulated for the hypersecretion of aldosterone usually seen in patients with chronic renal failure.

A technique has been developed for the quantitative estimation of perfusible glomeruli in the normal and diseased kidney. This technique is a modification of that originally described by Cook and Pickering (5). It entails the perfusion of the intact or excised kidney under standardized conditions with magnetic oxide of iron, which specifically localizes in the glomerular capillaries. The kidney is then emulsified and ground through a 100-mesh copper wire sieve and passed through an electromagnetic field. The magnetized glomeruli adhere to the glass under the influence of the magnetic field, the rest of the suspension passing through. The suspension is run through the electromagnetic field four or five times with the recovery of at least 90% of the glomeruli. The glomeruli are suspended in 30% aqueous solution of PVP and counted under microscopic vision on a scored glass microscope slide. The perfusible glomeruli and creatinine clearance of rats, ages 1 to 18 months and rabbits, ages 1 week to six months, have been determined and indicate that in the rat there is no increase in glomerular counts with maturation (mean 3.78 × 10⁴); GFR per glomerulus reaches the adult level by four weeks. In the rabbit the number of perfusible glomeruli increased from 5.5 × 10⁴ at one week to the adult level of 19.3 × 10⁴ at 1 month. There is a progressive increase in GFR per glomerulus from one week through six months, thus indicating the pattern of structural and functional maturation of the glomerulus in rat and rabbit. The collagen and non-collagen nitrogen in these animals was also studied. The techniques appear applicable to the study of the diseased kidney.

Renal biopsies from fifteen patients with unilateral renal arterial hypertension have been evaluated. In all cases, biopsies of the ipsilateral (‘ischemic’) kidney were obtained. In ten cases, biopsies of the contralateral (‘non-ischemic’) kidney were also obtained. An inverse correlation was found between the results of renal revascularization and the amount of tubular atrophy and interstitial scarring of the ‘ischemic’ kidney. Other pathologic parameters, including juxtaglomerular size and granularity and degree of arteriolar hyalinosis, showed little prognostic significance. It is concluded that with unilateral renal artery stenosis, renal revascularization generally will not significantly reduce elevated arterial pressure in the presence of severe ipsilateral tubular atrophy and interstitial scarring.

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