Glucose turnover and oxidation are increased in the iron-deficient anemic rat

To test the hypothesis that glucose metabolism is altered by iron deficiency, rates of glucose turnover and oxidation were assessed concurrently with the metabolic rate (VO2) in iron-deficient anemic rats and in normal rats at rest. Male Sprague-Dawley rats, 21 days old, were fed a diet containing either 6 mg iron/kg feed (iron-deficient group) or 50 mg iron/kg feed (iron-sufficient control group) for 3-4 wk. After dietary treatment the iron-deficient group was anemic, with hemoglobin levels of 5.8 +/- 0.2 g/dl, compared with 13.8 +/- 0.4 g/dl for controls. To study glucose metabolism, rats received a 90 min primed-continuous infusion of [6-3H]-and [U-14C]glucose via an indwelling jugular catheter. Serial blood samples were removed from a carotid catheter for determination of glucose concentration and specific activity. Expired air was monitored for VO2, VCO2, and 14CO2. The VO2 (ml X kg-1 X min-1) of iron-deficient rats was 20% higher than controls. Iron-deficient rats had a greater rate of glucose turnover (94 +/- 4 vs. 52 +/- 3 mumol X kg-1 X min-1) and a greater glucose recycling rate, even when normalized to VO2. Despite a higher blood glucose concentration (5.5 +/- 0.6 vs. 4.1 +/- 0.1 mM), the metabolic clearance rate was greater in iron-deficient animals (18 +/- 1 vs. 13 +/- 1 ml X kg-1 X min-1).(ABSTRACT TRUNCATED AT 250 WORDS)