Emily N. Loeb

The Development of Hypertension and Nephritis in Normal and Adrenalectomized Rats Treated With Cortisone.

Summary 1. The administration of cortisone did not prevent the development of experimental cytotoxic serum nephritis in the rat. 2. Moderate hypertension developed in nephritic rats with intact adrenal glands when injected with cortisone, whereas striking hypertension appeared in adrenalectomized nephritic rats similarly treated. 3. The nephritic rats rendered hypertensive by the administration of cortisone presented no greater histological evidence of renal damage than did normotensive control nephritic animals.

THE ASSOCIATION OF TYPE SPECIFIC HEMOLYTIC STREPTOCOCCI WITH ACUTE GLOMERULONEPHRITIS : AT THE PRESBYTERIAN AND BABIES HOSPITALS, NEW YORK, N. Y., IN THE YEARS 1936-1942

The mechanism by which acute glomerulonephritis develops is unknown, but there is general agreement that an infection initiates the process. This infection commonly occurs in the upper respiratory tract but classical instances of acute glomerulonephritis have followed infections of the skin, subcutaneous tissues, lungs and peritoneal cavity. An antecedent hemolytic streptococcal pharyngitis has not been excluded in all these instances. Clinical, bacteriological and immunological evidence indicates that the hemolytic streptococcus is the precipitating agent in the great majority of the infections that precede acute glomerulonephritis (1-7). It should be noted, however, that acute glomerulonephritis has followed pneumococcic pneumonia (8), subacute bacterial endocarditis (9), and gastrointestinal infections due to various enteric organisms (1). Recently Rammelkamp, Weaver, and Dingle (10) presented evidence indicating that the attack rate of acute glomerulonephritis following Group A hemolytic streptococcus infections varied considerably. In contrast, the incidence of acute rheumatic fever following such infections appeared to be relatively constant. Rammelkamp and his associates postulated that this difference in attack rate was due to the episodic appearance of certain strains of hemolytic streptococci which were more nephritogenic than others. Their collected data

Effect of Anti-Placenta Serum on Development of Foetus in the Pregnant Rat

Conclusion (1) Rabbit-anti-rat-placenta serum effectively interferes with the normal development of the placenta and foetus in the pregnant rat. (2) The same result is obtained with much smaller injections of rabbit anti-rat-whole-blood serum. (3) Rabbit anti-rat-serum serum fails to influence pregnancy unless injected in sufficient volume to induce anemia. (4) Anti-hormone serum and normal rabbit serum are without effect on pregnancy in the rat. (5) The immunological factor or factors responsible for the resorption of the foetuses following the injection of anti-placental serum and anti-whole-blood serum are as yet unknown.

Depletion of Carcass Potassium in Rats Made Hypertensive With Desoxycorticosterone Acetate (DCA) and With Cortisone

The hypertension which can be induced experimentally in rats by the administration of desoxycorticosterone acetate (DCA) differs from that which develops in rats given cortisone acetate in its dependence upon a liberal sodium intake (1). Not only is DCA-hypertension made more severe by providing the animals with excess sodium (2), but it fails to develop if the available supply of this cation be sufficiently restricted (3). In contradistinction, the capacity of cortisone (1) or of hydrocortisone (4) to elevate the blood pressure is independent of sodium intake. It seemed of interest, therefore, to determine whether the mechanisms underlying the dissimilar actions of these two groups of steroids would be reflected in the electrolyte composition of the tissues of animals given one or the other compound under conditions of sodium loading as well as of sodium restriction. A preliminary study analyzing pooled samples of tissue indicated that the hypertension induced by DCAwas accompanied by an increase in carcass sodium, whereas this did not obtain in the carcasses of rats made hypertensive with cortisone (5).

Development of Hypertension in the Adrenalectomized Nephritic Rat Maintained on NaCl.

Summary In response to cytotoxic serum nephritis, bilaterally adrenalectomized rats develop hypertension as frequently as do animals with intact adrenals. In order for hypertension to appear among such adrenalectomized rats, it is necessary that a satisfactory state of nutrition be maintained over a period of weeks. In our laboratory, the difficulties encountered in fulfilling this provision have been considerable in spite of the employment of a high NaCl regimen. This experience has led us to wonder whether the conflicting results in the literature relating to the question of hypertension in adrenalectomized animals may not be due, in part, to similar difficulties.

THE COMBINED EFFECT OF CORTISONE ACETATE AND DESOXYCORTICOSTERONE ACETATE IN ADRENAL-ECTOMIZED RATS ON A LOW SODIUM DIET

In a previous report the authors have described the response of young adrenalectomized rats to desoxycorticosterone acetate (DCA) and to cortisone acetate (CA) when maintained on a diet severely restricted in sodium content (1). Daily injections of 2.5 mg. of DCAresulted in progressive weight gain and maintenance of normal blood pressure, while similar doses of CA were accompanied by rapid weight loss and arterial hypertension. With both steroids terminal serum sodium values were within normal range. The present experiments describe the results obtained over a wide range of dosages of DCA2 and CA,8 given singly and in varying combinations, and were undertaken in an attempt to determine to what extent the individual action of each steroid was modified by concomitant administration of the other.

Failure of Liver Feeding to Counteract Cortisone Effects Other than Growth Inhibition

Conclusion 1. Desiccated liver powder as a dietary supplement to a low sodium diet is effective in counteracting the growth inhibition induced by cortisone acetate in rats only if the steroid is presented orally. It is without demonstrable effect in animals receiving the hormone by injection. It is also without effect in adrenalectomized animals, irrespective of the route of hormone administration. 2. The prevention of growth inhibition by liver powder is not accompanied by other evidences of diminished cortisone activity, i.e., despite normal growth such animals exhibit physiological, anatomical and biochemical changes of the same degree as do cortisone treated rats without liver supplement.