Fig. 6.

PH alters the metabolic phenotype in both the RV and the LV. Protein expression of pyruvate kinase (PKM) 1 (A) and PKM2 (B) was unchanged by exposure to hypobaric hypoxia; however, the ratio between 1 and 2 isoforms (C) was significantly diminished as a result of HH. PKM1 and -2 were assessed by immunoblotting and normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH); n = 10 in each condition. Real-time PCR was used to assess transcriptional changes in PKM1 and PKM2 isoforms as a result of hypobaric hypoxia. PKM1 (D) and PKM2 (E) were unchanged by HH; however, the ratio between 1 and 2 was attenuated in HH (F), with a significant interaction between the right and left ventricles; n = 6 in each condition. PFK1 (G) and glucose transporter 4 (GLUT4, H) protein expression was upregulated in both ventricles, or unchanged, respectively, as a result of HH; n = 10 in each condition.