Fig. 4

The regulation of erythropoietin production in Slc7a7 knockout mice involves hypoxia-independent pathways. a Immunofluorescence staining of y⁺LAT1 protein (Red, Slc7a7) revealed positive localization on the basolateral side of proximal convoluted tubules in kidney sections from control and Slc7a7^KO mice. DAPI (blue) was used to stain the nuclei. Scale bar: 100 μm. Representative images from 3 independent mice per genotype are shown. b Left: Immunohistochemical staining of HIF-2 (brown) in kidney sections from control and Slc7a7^KO mice. Right: Quantification of the HIF-2-positive area revealed no significant differences between genotypes. Scale bar: 250 μm. c Schematic representation of the experimental protocol used to evaluate the effect of dimethyloxalylglycine (DMOG, 500 mg/kg) on erythropoietin production in control and Slc7a7^KO mice. The mice were treated with tamoxifen for 7 days followed by a 10-day low-protein diet, with DMOG administered 5 h prior to sacrifice. d Real-time RT‒PCR analysis of Epo gene expression in kidney tissue after DMOG administration. e Serum erythropoietin concentrations in control and Slc7a7^KO mice after DMOG treatment. All the data are presented as the means ± SEMs. Statistical analysis was performed via a two-tailed unpaired Student’s t test. Each data point represents a single animal