title: Physiological correlates of locomotory performance in a lizard: an allometric approach.
abstract: Three measures of locomotory performance and a series of variables thought to affect performance were measured in the iguanid lizard Ctenosaura similis. Burst speed is mass independent; however, endurance time at 1 km/h (EN-DUR) and maximal distance run (MAX DIS) scale as M0.3. Standard and maximal rates of O2 consumption (VO2max) scale as M0.9; VO2max averages 10-fold greater than standard metabolic rate (SMR). Three of ten enzyme activities measured exhibit significant scaling. After statistically removing the effects of body mass, multiple-regression analysis indicates that 1) 89% of the residual variation in ENDUR is correlated with variation among individuals in thigh muscle mass, VO2max, heart mass, and liver citrate synthase (CS) activity; 2) maximal CO2 consumption (VCO2max) and thigh pyruvate kinase activity statistically explain 64% of the variation in MAX DIS; 3) heart and liver masses together predict 35% of the variation in SMR; 4) thigh and liver CS activity, heart lactate dehydrogenase (LDH) activity, and hematocrit account for 67% of the variation in VO2max;5) 97% of the variation in VCO2max is statistically related to variation in liver CS activity, thigh and heart masses, and heart LDH activity.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001824:Body Constitution; D001831:Body Temperature; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004734:Energy Metabolism; D006400:Hematocrit; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008116:Lizards / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D009210:Myofibrils / Q000201:enzymology; D005082:Physical Exertion; D011770:Pyruvate Kinase / Q000378:metabolism
chemical_list: D007770:L-Lactate Dehydrogenase; D002950:Citrate (si)-Synthase; D011770:Pyruvate Kinase; D000251:Adenosine Triphosphatases