Reduced Metabolic Rate in Acute Uremic Rats: Interrelations between Bilateral Nephrectomy and Anesthesia

Prof. Dr. M. Hohenegger, Institut für Allgemeine und Experimentelle Pathologie, Währingerstrasse 13, A-1090 Wien (Austria) Dear Sir, The bilaterally nephrectomized rat is a frequently employed experimental model in uremia research. According to our previous investigations [8], the metabolic rate of such animals is severely reduced independently of body temperature and blood pH. Reduced oxidative metabolism may influence secondarily other metabolic data studied in these rats. Since many experiments in acute uremia have to be performed under anesthesia, and our previous results were obtained in awake rats only, we investigated whether or not anesthesia induces a further reduction of the metabolic rate in acute uremia. Results Oxygen consumption is reduced about 20–30% in anesthetized non uremic rats. It is reduced about 50–60% in the uremic animals. Uremic rats are still conscious during this period and their activity is not essentially reduced. According to previous investigations [8, 9] in such uremic rats plasma urea is in the range of 400–600 mg/dl, arterial blood pH between 7.1 and 7.2 [9]. The metabolic rate of these uremic rats is not reduced further by anesthesia of both types (table I). In anesthetized uremic rats p02 was 102 ± 8.1 mm Hg, pC02 34.4 ± 6.5 mm Hg (n = 14). In non uremic anesthetized animals the corresponding values for p02 were