ADAPTIVE-CHANGES OF LACTATE-DEHYDROGENASE IN WHITE SKELETAL-MUSCLE OFTHE SEA-TROUT SALMO-TRUTTA L

Time-related changes of the lactate dehydrogenase (LDH) reaction in wh ite skeletal muscle were considered in three ecological groups of sea trout: river dwarf males, diadromous, and lake-river individuals, that differ in mode of life, distribution, and preferred temperatures. The main characteristics of the LDH-reaction, enzyme-substrate affinity, reaction rate, and temperature coefficient Q(10), were studied in the temperature range from 1 to 25 degrees, which coincides with the limit s of temperature changes in nature. Despite some differences in biolog ical features, the main characteristics studied of the enzymatic react ion changed in a similar way in the area of temperature studied. Adapt ive aspects of the wide reaction norm of this biochemical process are discussed with special reference to energy metabolism in the polymorph ic species (sea trout).