Adaptations of Lactate Metabolism in Iron-Deficient Rats

Abstract

Effects of dietary iron deficiency on lactate metabolism were studied in weanling female rats. Following an iron-deficient diet for 5 weeks, mean hemoglobin concentration was lowered to 6.4 g/dl relative to 12.2 in the control group. Mean plasma iron levels were 58 and 162 μg/dl, respectively. Significantly elevated resting lactate levels were observed in whole blood and plasma from iron-deficient anemic (relative to control) rats. Total activity of lactate dehydrogenase (LDH) was elevated in soleus and gastrocnemius muscles in response to iron deficiency from 269 ± 51 to 364 ± 60 (Mean ± SD) and from 265 ± 65 to 372 ± 61 IU·10⁻³·g^–1, respectively. The LDH activity in heart was lowered from 700 ± 61 to 593 ± 45 IU·10⁻³·g^–1. The M₃H and M₂H₂ isozymes in soleus were increased from 12.7 ± 2.8 to 20.4 ± 5.8% and from 19.4 ± 6.1 to 28.2 ± 3.6%, respectively. Similar increase was observed in M₂H₂ and MH₃ in gastrocnemius from 9.8 ± 0.9 to 14.8 ± 2.0% and from 17.4 ± 2.0 to 20.5 ± 2.3%, respectively. The H₄ isozyme was significantly reduced in soleus, gastrocnemius, and plantaris muscles from 27.7 ± 4.7 to 12.4 ± 4.4, from 15.8 ± 1.9 to 7.2 ± 2.9, and from 10.5 ± 2.9 to 3.9 ± 2.1%, respectively. It was suggested that iron-deficiency anemia induces an elevation of lactate production following an increase in total LDH activity and change in LDH isozyme patterns.