Seasonal acclimatization in anuran amphibians: Changes in lactate dehydrogenase specific activities and isoenzyme patterns in several tissues from a naturally occurring population of Discoglossus pictus pictus (Otth.)

Abstract

1. 1. The effect of seasonal acclimatization over lactate dehydrogenase (LDH) specific activities and isoenzyme patterns from sartorius muscle, liver, heart and brain was studied in Discoglossus pictus pictus (Otth.). 2. 2. When measured at 30°C, LDH specific activity in muscle, heart and brain is maximal during autumn and minimal during spring. In liver there is only a drop in spring. 3. 3. There is an increase in H-type LDH isoenzyme activities during summer in liver, a decrease in these during winter and summer in heart, and a continuous decrease in M-type activities from autumn to summer in brain. 4. 4. The kinetic effect of environmental temperature over LDH catalytic activities and the data from a previous cold acclimation study are discussed. 5. 5. The variations in behavioural activity (and their metabolic consequences) and the existence of a circannual rhythm in D. pictus metabolism are suggested as responsible for the enzymatic changes.