The American journal of physiology
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Acute isovolemic anemia was produced in anesthetized chickens by serial exchanges of 6% dextran 70 equal to 1% of body weight to quantitate cardiovascular and metabolic parameters. When hematocrit (Hct) and hemoglobin (Hb) levels were reduced by 50% (from 33.3 to 16.3 vol %, and from 10.3 to 5.4 g/100 g, respectively, P less than 0.001), tissue oxygen delivery was maintained by increases in cardiac output (CO), stroke volume (SV), oxygen extraction, and reduced total peripheral resistance (TPR). ⋯ Relative apparent viscosity determinations on the exchanged blood-dextran mixtures indicated that large viscosity changes occurred with the first exchange whereas subsequent exchanges had small incremental viscosity changes. These data indicate that in acutely anemic chickens, oxygen transport capacity was maintained by increased cardiac output and decreased peripheral resistance, unless the severity of the anemia resulted in cardiovascular failure.
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Ketosis was produced by intravenous infusion (5 mmol/kg per h) of [3-14C]acetoacetate (sp act 0.5 muCi/mmol) into fed and 7-day-fasted sheep. Changes in arterial and sagittal sinus blood samples. During acetoacetate infusion, there was a significant increase in ketone body uptake (P less than 0.001) and conversion to 14CO2 in both fed and fasted sheep. ⋯ The plasma insulin concentration was increased significantly both in fed and fasted animals. These results indicate that ovine brain can utilize ketone bodies irrespective of nutritional state. In addition, ketone bodies stimulated the production of lactate by ovine brain.