Figure 3
The regulating function \(\Omega _{E} = \frac{[\text{PYR}_E*]^4}{[\text{PYR}_E*]^{4}+[\text{PYR}_E]^4}\) (blue line), and its complement \(\Phi _{E} = (1-\Omega _{E})\) (orange line) take values between 0 and 1 depending on the concentration of [PYR\(_E\)] with respect to the constant [PYR\(_E\)*]. This parameter represents the healthy RPE’s requirement of pyruvate, and determines the proportion of glucose that the RPE keeps for its own glycolysis pathway, and the proportion that it is diverted to the rods. For low \(\Omega _{E}\) (high \(\Phi _{E}\)), the RPE’s glucose utilization is blocked (and redirection of glucose to the photoreceptors is favored). Conversely, high \(\Omega _{E}\) (low \(\Phi _{E}\)) favors the RPE’s retention of glucose, activating its glycolysis (and blocking the transport of glucose to the rods). Both lines intersect at precisely [PYR\(_E\)] = [PYR\(_E\)*] (red star).
