Figure 2.

The synthesis of amino acids from proline occurs mostly in the RPE but not the neural retina ex vivo in mice.A, a schematic of ex vivo incubation of mouse RPE/choroid (RPE/Cho) and retina with ¹⁵N proline. Tissues were incubated with ¹⁵N proline in Krebs–Ringer bicarbonate buffer (KRB) for 0, 0.5, 1, and 2 h. Tissues and media were collected at these time points for metabolite analysis with GC–MS. B, ¹⁵N proline consumption from RPE/Cho and retina. ∗∗∗p < 0.001, N = 4. C–K, ¹⁵N fraction of metabolites derived from ¹⁵N proline in RPE/Cho and retina at different time points. Error bars represent SD. RPE, retinal pigment epithelium.