As the data from the three studies presented above were analyzed, it became evident that there were interesting differences in vitamin A kinetics as a function of vitamin A status. Thus, in a 1987 paper (Green et al., 1987), we compared plasma tracer kinetics at three levels of vitamin A status using empirical compartmental modeling (Green and Green, 1990a,b). In this approach, observed plasma tracer data are fit to a multiexponential equation, and kinetic parameters such as vitamin A disposal rate, plasma fractional catabolic rate, transit and residence times, and recycling number are computed from the curves' exponential constants and coefficients. As is evident in Fig. 4, there are dramatic differences in the steepness of the bend
Was this article helpful?