RESUMEN
To determine whether chloride-depletion metabolic alkalosis (CDA) can be corrected by provision of chloride without volume expansion or intranephronal redistribution of fluid reabsorption, CDA was produced in Sprague-Dawley rats by peritoneal dialysis against 0.15 M NaHCO3; controls (CON) were dialyzed against Ringer's bicarbonate. Animals were infused with isotonic solutions containing the same Cl and total CO2 (tCO2) concentrations as in postdialysis plasma at rates shown to be associated with slight but stable volume contraction. During the subsequent 6 h, serum Cl and tCO2 concentrations remained stable and normal in CON and corrected towards normal in CDA; urinary chloride excretion was less and bicarbonate excretion greater than those in CON during this period. Micropuncture and microinjection studies were performed in the 3rd h after dialysis. Plasma volumes determined by 125I-albumin were not different. Inulin clearance and fractional chloride excretion were lower (P less than 0.05) in CDA. Superficial nephron glomerular filtration rate determined from distal puncture sites was lower (P less than 0.02) in CDA (27.9 +/- 2.3 nl/min) compared with that in CON (37.9 +/- 2.6). Fractional fluid and chloride reabsorption in the proximal convoluted tubule and within the loop segment did not differ. Fractional chloride delivery to the early distal convolution did not differ but that out of this segment was less (P less than 0.01) in group CDA. Urinary recovery of 36Cl injected into the collecting duct segment was lower (P less than 0.01) in CDA (CON 74 +/- 3; CDA 34 +/- 4%). These data show that CDA can be corrected by the provision of chloride without volume expansion or alterations in the intranephronal distribution of fluid reabsorption. Enhanced chloride reabsorption in the collecting duct segment, and possibly in the distal convoluted tubule, contributes importantly to this correction.
Asunto(s)
Alcalosis/metabolismo , Cloruros/metabolismo , Fluidoterapia , Volumen Plasmático , Absorción , Alcalosis/fisiopatología , Alcalosis/terapia , Animales , Bicarbonatos/administración & dosificación , Presión Sanguínea , Cloruros/administración & dosificación , Cloruros/sangre , Tasa de Filtración Glomerular , Inulina , Soluciones Isotónicas , Pruebas de Función Renal , Masculino , Diálisis Peritoneal , Ratas , Ratas EndogámicasRESUMEN
Carbohydrate metabolism was studied during a 72-hr fast in 11 nondiabetic endstage renal disease (ESRD) patients on chronic hemodialysis and six normal subjects. Blood was obtained every 12 hr for metabolic substrate, insulin, and potassium concentrations. Serum potassium concentrations were significantly higher in the ESRD patients at the end of each fasting day, and two patients were removed before completion of the fast when severe hyperkalemia developed. Mean blood glucose, alanine, pyruvate, beta-hydroxybutyrate, and serum insulin concentrations were similar in the two groups. Mean blood lactate concentration tended to be higher in the ESRD group. Mean blood acetoacetate and plasma free fatty acid (FFA) concentrations were lower in the ESRD group. When compared to serum insulin levels, the FFA concentration was lower in the ESRD group.