Metabolism of salt-retaining hormone by surviving liver slices

Role of the kidney in the pathogenesis of congestive heart failure

The pathogenesis of sodium retention in congestive heart failure has been a difficult problem to elucidate. The production in dogs of cardiac valvular lesions of increasing severity has enabled investigators to study the sequential alterations in salt and water balance in the same animal from the normal state through the progressive stages of cardiac impairment until frank failure is present. The findings in dogs suggest that: 1. Abnormalities in sodium metabolism are detectable in mild heart disease long before overt failure is present. 2. Total exchangeable sodium may be increased in animals with mild valvular damage. These animals have normal exercise tolerance and normal basal glomerular filtration rates. 3. Increased sympatho-adrenal (adrenergie) activity is responsible, in large measure, for the decreased sodium and water excretion in dogs with cardiac impairment. 4. Preliminary experiments suggest that the carotid sinus may be the receptor organ initiating the reflex increase in sympatho-adrenal tone, and may be the elusive "volume receptor" for which investigators have been searching. 5. Evidence is also available that the carotid sinus may play a major role in the regulation of the zona glomerulosa of the adrenal cortex, the site of aldosterone production.

Glucose intolerance in sarcoma patients

Twenty-seven otherwise healthy patients with localized sarcoma were examined to determine if glucose intolerance can be detected before the appearance of clinical signs of cachexia. No patient had lost weight or demonstrated severe malnutrition. Fasting plasma samples for glucose, insulin, glucagon, and free fatty acids (FFA) were obtained, and a standard intravenous glucose tolerance test performed. Glucose disappearance rate (K) was calculated between 5 and 60 minutes. K levels were compared to those of normal controls and to those of patients with more extensive cancer (statistics obtained from the literature). Levels for K were compared to tumor volume measurements following surgery. Fasting glucose, insulin, and glucagon levels were normal. Fasting FFA levels were slightly elevated. K levels for sarcoma patients were significantly lower than in control patients (P = 0.04), and higher than in patients with advanced cancer (P less than 0.0001). The subset of patients who weighed less than the ideal had a significantly lower K level than did the rest of the sarcoma population. K levels correlated inversely with tumor volume (r = -0.34; P = 0.04). These data indicate that mild glucose intolerance (reduction in clearance of a glucose load) occurs early in untreated sarcoma patients, is most prevalent in patients who maintain less than the ideal weight, correlates with tumor burden, and occurs before other signs of cachexia appear.

THE METABOLISM OF ALDOSTERONE BY SURVIVING DOG AND HUMAN LIVER SLICES

Surviving dog liver slices were incubated with d,l-aldosterone-21-monoacetate, d,l-aldosterone, d-aldosterone, and d-aldosterone-21-C14. Human liver slices were incubated with d,l-aldosterone-21-monoacetate and d-aldosterone. The incubations were performed in a Krebs–Ringer–phosphate medium (pH 7.4), with 200 mg glucose added per 100 ml of medium, at a temperature of 37 °C. After incubation, the medium was extracted with chloroform and the crude extract extensively fractionated on column and paper chromatographic systems. In addition to free aldosterone, four metabolic products were isolated, two ring A reduced α-ketolic and two ultraviolet absorbing, non-reducing substances. The partial chemical characterization of these metabolites was attempted. The search for aldosterone metabolites in human urine resulted in the isolation of a substance in acetate form from the urine of a patient suffering from primary aldosteronism which may be identical with one of the ring A reduced metabolites obtained in the in vitro experiments.