losartan-potassium and Alkalosis--Respiratory

The purpose of this study was twofold: (1) to define the relationship between erythropoietin (Ep) production and some of the coincident variables which control oxygen delivery in hypoxic and hypoxic-hypercarbic rats (2) to define the mechanism whereby hypercarbia suppresses Ep production in hypoxemic rats. Rats were exposed to O2 concentrations ranging from 5% to 9% O2 for either 3 or 16 h. Arterial whole blood pH, pCO2, pO2, O2 saturation, p50 and Ep levels were measured in each rat. There was a highly significant inverse correlation between both the arterial pO2 and O2 saturation and the Ep level. Ep levels were not increased above normal if the pO2 was greater than 50 mm Hg or the O2 saturation was greater than 80%. The addition of 5% CO2 to all inhaled gas mixtures was associated with a 10 mm Hg increment in the pO2 together with a marked reduction in plasma Ep levels. Of the measured variables only the pO2 and O2 saturation showed a consistent correlation with the Ep levels when rats exposed to hypoxia were compared with rats exposed to hypoxia + CO2.

Topics: Alkalosis, Respiratory; Animals; Carbon Dioxide; Erythropoietin; Female; Hydrogen-Ion Concentration; Hypercapnia; Hypoxia; Iron; Oxygen; Rats

The mechanism of erythropoietin (Ep) production after acute haemorrhage has been thought to be due to a reduction in blood volume and tissue perfusion leading to tissue hypoxia. In the present study we have evaluated the effect of acute haemorrhage in the rat on the acid-base status, the red cell affinity for oxygen in vivo, and Ep production. Within a few hours after acute blood loss there was a respiratory alkalosis with an increase in blood pH, a decrease in pCO2 and an increase in the red cell affinity of Hb for oxygen in vivo that was temporally related to an increase in Ep production. Within 24 h after the acute haemorrhage, the blood pH AND PCO2, red cell affinity for oxygen in vivo, and Ep level returned towards normal. The decrease in in vivo red cell affinity for oxygen was associated with an increase in red cell 2,3-DPG levels and a decrease in Ep production.

Topics: Acid-Base Imbalance; Acute Disease; Alkalosis, Respiratory; Animals; Diphosphoglyceric Acids; Erythrocytes; Erythropoietin; Female; Hemorrhage; Oxyhemoglobins; Partial Pressure; Rats

Topics: Alkalosis, Respiratory; Animals; Carbon Dioxide; Carboxyhemoglobin; Chlorides; Cobalt; Dose-Response Relationship, Drug; Erythropoietin; Female; Hydrogen-Ion Concentration; Iron Radioisotopes; Male; Nephrectomy; Oxygen; Partial Pressure; Rats; Spectrophotometry

Topics: Acetazolamide; Acid-Base Equilibrium; Adult; Alkalosis, Respiratory; Altitude; Blood; Capillaries; Carbon Dioxide; Diphosphoglyceric Acids; Erythrocytes; Erythropoietin; Hemoglobins; Humans; Hydrogen-Ion Concentration; Hypoxia; Male; Oxygen; Phosphorus

Topics: Acetazolamide; Alkalosis, Respiratory; Animals; Blood; Erythropoietin; Female; Hemoglobins; Hydrogen-Ion Concentration; Hypoxia; Iron Radioisotopes; Oxygen; Oxyhemoglobins; Partial Pressure; Rats