Allometry (scaling) of blood components in mammals: connection with economy of energy?

To access full text version of this article. Please click on the hyperlink "View/Open" at the bottom of this pageHematocrit (HCT), blood hemoglobin (HGB), and serum concentrations of 14 commonly measured serum constituents in mammals were extracted from 131 publications published within the last 35 years and then subjected to allometric study (Y = aWb, where Y is the characteristic studied, W is body mass, and b is the scaling exponent). HCT and HGB values decreased (b 0; p < 0.02 and p < 0.001, respectively) with W. The associations of HCT, HGB, glucose, triglycerides, and urea values with W may be assumed to coincide with the well-known reduction of metabolic rate per unit mass with increasing W of mammals. The decrease in serum K+ values (p < 0.001) has yet to be adequately explained. Despite the ratio of muscle mass and W being constant for large and small mammals, serum values of creatinine rose (b = 0.14; p < 0.0001) with W. This suggests increased phosphocreatine turnover in muscles with W, which in turn might be connected to the increased efficiency reported for leg muscles in larger animals and, conceivably, might affect the measurement of metabolic rate and hence its scaling in mammal