Estimation of a derivative by a difference quotient: its application to hepatocyte lactate metabolism

Values of the derivative of a convex function are estimated from data for the function by assigning the difference quotients of the observations to appropriate values of the determining variable. The procedure is illustrated for the time course of hepatocytes incubated with lactate, of amount l, for which pyruvate, of amount p, is also observed. An empirical linear relation between dp/dt and ln(l/p) is established.