PSII-17 - The differential expression pattern of messenger RNA for key hepatic glycogen metabolizing proteins is consistent with hepatic glycogen content in suckling pigs

The effect of developmental age (d) on expression of genes responsible for hepatic glycogen (GLY) synthesis and degradation, glucose flux, and GLY content, was determined in crossbred pigs euthanized (n = 6) at birth (d 0, pre-suckle), 1, 3, 7, 14, and 21 d. Liver GLY content and relative abundance of mRNA (RT-PCR) was determined. The relative content of liver mRNA was determined in 2 experiments, d 0, 1, 3, 7 (Experiment 1) and d 0, 1, 7, 14, 21 (Experiment 2). Within each experiment, data were analyzed using the GLM procedure of SAS. Fisher’s protected LSD procedure was used to separate treatment means. Day 0 (76.0) GLY content (mg/g) decreased (P < 0.01) 82% from d 0 to d 1, increased (P < 0.05) from d 1 (13.8) through d 14 (28.4), and did not differ (P = 0.07) between d 1 and 21. In Experiment 1, mRNA content of GLY synthesis proteins GYG1 and GYS1 was greatest (P < 0.01) at d 3 and 7; and 1 and 3; respectively, whereas mRNA content of GLY degrading proteins PGM1, PGM2, and PGM5 was greatest (P ≤ 0.01) at d 1; d 0; and d 1 and 7; respectively. In Experiment 2, mRNA content of GLY synthesis proteins GBE1 and GYS1 was greatest (P < 0.01) at d 0 and 21; and d 1 and 21; respectively, whereas mRNA content of GLY degrading proteins AGL, PGM2, PGM2L, and PGM5 was greatest (P < 0.01) at d 21; d 0; d 7, 14, and 21; and d 14 and 21; respectively. Glucose transporter SGLT1 mRNA content was greatest (P < 0.01) at d 14 and 21. These findings indicate that the pattern of mRNA content of key hepatic GLY degradation and synthesis proteins was consistent with GLY content of suckling pigs.