THERMAL INDEPENDENCE OF MUSCLE-TISSUE METABOLISM IN THE LEATHERBACK TURTLE, DERMOCHELYS-CORIACEA

Metabolic rates of animal tissues typically increase with increasing t emperature and thermoregulatory control in an animal is a regional or whole body process. Here we report that metabolic rates of isolated le atherback turtle (Dermochelys coriacea) pectoralis muscle are independ ent of temperature from 5-38 degrees C (Q(10) = 1). Conversely, metabo lic rates of green turtle (Chelonia mydas) pectoralis muscle exhibit a typical vertebrate response and increase with increasing temperature (Q(10)-1.3-3.0). Leatherbacks traverse oceanic waters with dramatic te mperature differences during their migrations from sub-polar to equato rial regions. The metabolic stability of leatherback muscle effectivel y uncouples resting muscle metabolism from thermal constraints typical of other vertebrate tissues. Unique muscle physiology of leather back s has important implications for understanding vertebrate muscle funct ion, and is another strong argument for preservation of this endangere d species. (C) 1998 Elsevier Science Inc. All rights reserved.