Contrasting action of short- and long-term adrenaline infusion on dog skeletal muscle glucose metabolism.

摘要: There are important differences between the short- and long-term effects of adrenaline on determinants glucose tolerance. To assess this metabolic adaptation at tissue level, present study examined effect acute prolonged in vivo elevation glycogen metabolism glycolysis skeletal muscle. Adrenaline (50 ng · kg−1 min−1) was infused for 2 h or 74 results compared with 1 0.9% NaCl infusion six trained dogs. Muscle content reduced by (161 ± 17 vs 250 24 μmol/g dry weight;p < 0.05) but not short-term (233 21) indicating a sustained metabolism. Acutely, synthase I (short-term 12 6 NaC122 7μmol glycosyl units g−1 min−1;p returned to normal (20 5). In contrast, Km phosphorylasea changed acutely 31 27 7 mmol/1 inorganic phosphate) during (19 4;p 0.05 adrenaline). Thus, infusion, there were different enzyme changes, although likely promote glycogenolysis both cases. glycolytic pathway substrates 6-phosphate fructose did change significantly hexokinase inhibited. phosphofructokinase had Vmax 34 44 5 U/g; p still above maximal operating rate vivo. With (long-term 0.32 0.03 0.44 0.07 mmol/l 6-phosphate;p 0.05). situation relatively low flux, glycogenolytic mediated increased phosphorylase ctivity occurs without significant accumulation hexose monophosphates impairment glycolysis.