Figure 4.

Determination of $V_{\text{max}}^t$, $V_{\text{max}}^{\mathit{\text{util}}}$, $K_{\text{m}}^t$ and $K_{\text{m}}^{\mathit{\text{util}}}$ from acetate data in one animal in group 3. (A) Best fits (represented by solid line) obtained after simultaneously fitting the time course of brain acetate concentration for one animal in group 3 together with the curve [S_brain] = f([S_plasma]) at steady-state obtained from data from all animals in all four groups. In this particular example, the fitted values of transport parameters were $V_{\text{max}}^t=1.02\mathrm{\mu }\text{mol}/\text{g}/\text{min}$, $V_{\text{max}}^{\mathit{\text{util}}}=0.55\mathrm{\mu }\text{mol}/\text{g}/\text{min}$, $K_{\text{m}}^t=4.4\text{mM}$ and $K_{\text{m}}^{\mathit{\text{util}}}=0.01\text{mM}$. The calculated CMR_ace as a function of time for the same animal showed a rapid increase before reaching its steady-state value (0.54 μmol/g/min) in about 10 min following [2-¹³C]acetate infusion. The blood acetate concentration which was used as input function for fitting the dynamic data is also shown.