Sheldon Rosenfeld

Spontaneous hydronephrosis in the rat.

Summary 1) Spontaneous right hydronephrosis occurs in approximately half the animals in an inbred strain of Slonaker-Addis albino rats. The lesion disappears in female rats as they exceed 200 g weight. 2) The abnormality is produced by partial constriction of the right ureter by the ovarian or spermatic artery. 3) Hydronephrosis does not appear to predispose the animals to spontaneous infection in the abnormal kidney. The authors express their thanks to Drs. David Zion, Dept. of Radiology and to Maurice White, Dept. of Bacteriology, for aid in this study.

Enhancement of experimental atherosclerosis by ACTH in the dog.

Summary One to 3 injections of 40 units of ACTH-gel significantly enhanced the elevated serum cholesterol and phospholipid levels produced by subsequent thiouracil and cholesterol feeding in the dog. This effect was associated with paralytic strokes in 4 of 10 dogs. Autopsy revealed markedly more widespread and more severe atherosclerosis in dogs pretreated with ACTH than in dogs who received only a high thiouracil and cholesterol diet. The authors are indebted to Drs. Wilfrid Dixon and Frederick Moore for statistical evaluation of the data and Drs. John Mehl and Ross Jacobs for supervision of lipid and lipoprotein determinations.

Increased excretion of urinary corticoids by guinea pigs following administration of pitressin.

Summary Pitressin causes an increased excretion of urinary corticoids by the guinea pig. The presence of the anterior pituitary is necessary for this response. The increased corticoid excretion is not dependent upon the production of systemic hypertension by pitressin, nor is it due to adrenaline release, or the production of hyponatremia, or systemic anoxia. The significance of these findings is discussed in reference to the role of pitressin as a humoral mediator in the hypothalamic activation of the release of ACTH by the anterior pituitary.

Effect of Renin and Plasma Protein Loading on Albumin Catabolism in the Isolated Perfused Kidney.

Summary Using the isolated perfused rabbit kidney preparation, the relationship between proteinuria and albumin catabolism was studied in the absence of all other tissues and humoral substances of the body. The rate of breakdown of I131 screened rabbit albumin was studied in both the normal and the proteinuric perfused kidney. Proteinuria was produced in the normal perfused kidney by administration of renin or by elevation of the plasma protein concentration of the perfusion media. It was found that albumin catabolism was markedly increased in the perfused kidney during renin and protein loading proteinuria.

Effect of ouabain and potassium on isolated perfused rabbit kidney.

Summary The effect of various doses of ouabain was studied on the isolated perfused kidney. A pronounced and consistent diuresis and natriuresis did not occur until a dose of 0.085 mg of ouabain was used. Within 2-20 min after the administration of ouabain, renal vascular resistance increased causing an increase in perfusion pressure and a reduction in renal blood flow, urine excretion, sodium excretion, and creatinine clearance. Plasma potassium always rose after the administration of ouabain. At 20-60 min after the addition of ouabain renal vascular resistance fell, causing the perfusion pressure to return to normal. There was an increase in renal blood flow, urine excretion (+220%) p<0.01 sodium excretion (+215%) p< 0.02 and the creatinine clearance returned to normal. Plasma potassium remained elevated. When potassium chloride (KCl) was added to the perfusion after 3-4 control periods, the plasma K level was raised from an average of 4.9 meq/liter to 8.6 meq/liter and leveled off at 8.1 to 7.8 meq/liter after the addition of ouabain. A diuresis and natriuresis was also produced by the addition of KCl, but when 0.085 mg of ouabain was added 20-40 min after the addition of KCl, even greater diuresis (+147%) p<0.001 and natriuresis (+138%) p<0.01 were produced. There was little evidence for a K-induced inhibition of the ouabain diuresis and natriuresis.