Temperature acclimation in amphibians: Changes in lactate dehydrogenase activities and isoenzyme patterns in several tissues from adult Discoglossus pictus pictus (Otth.)

Abstract

1. 1. The effect of cold (8 ± 2°C) acclimation on the lactate dehydrogenase activities and isoenzyme patterns from sartorius muscle, liver, heart and brain of adult Discoglossus pictus pictus (Otth.) was studied. 2. 2. Two groups of animals were studied: one set of animals was trapped in October and another set in December. In both cases some of the animals were sacrificed upon collection and some others subjected to 5 months of acclimation at 8 ± 2°C before being sacrificed for analysis. 3. 3. A general trend towards a decrease in LDH specific activity was observed during cold acclimation. The magnitude of change, but not the direction, depends on both the tissue examined and the season at which the experiment was initiated. 4. 4. A complex LDH isoenzyme reorganization was also found in liver, heart and brain. In liver from Experiment 1 and in heart from both experiments, a relative maintenance in M-type LDH activity during cold acclimation was observed. However, in brain there was a relative maintenance of LDH 3 activity in both experiments. 5. 5. The low behavioral activity (and its metabolic consequences) and the existence of an intrinsic annual rhythm in D. pictus metabolism are suggested as responsible for the observed enzymatic changes.