A Comparison of Methods for Determining Compartmental Analysis Parameters

Publisher Website
Google Scholar
Abstract
The traditional method for determining compartmental analysis parameters relies on a visual selection of data points to be used for regression of data from each cellular compartment. This method is appropriate when the compartments are kinetically discrete and are easily discernible. Where treatment effects on compartment parameters are being evaluated, a more objective method for determining intial parameters is desirable. Three methods were examined for determining initial isotopic contents and half-times of 86Rb elution from cellular compartments using theoretical data with known parameters. Experimental data from roots of Douglas fir (Pseudotsugs menziesii [Mirb.] Franco) and barley (Hordeum vulgare L.) intact seedlings were also used. The 3 methods were a visually assisted, linear regression on data of semilog plot of isotope elution vs. time; a microcomputer-assisted, linear regression on semilog plot in which maximization of the square of the correlation coefficient (r2) was the criterion to determine data points needed for each regression; and a mainframe computer-assisted, direct nonlinear regression on elution data using a model of the sum of 3 exponential decay functions. The visual method resulted in the least accurate estimates of compartmental analysis parameters. The microcomputer-assisted and nonlinear regression methods calculated the parameters equally well.