G-1,6-P2, glycolysis, and energy metabolism during circulatory occlusion in human skeletal muscle.

The effect of circulatory occlusion on the content of glucose 1,6-bisphosphate (G-1,6-P2), glycogenolytic intermediates, and high-energy phosphates in the quadriceps femoris muscles of eight men was investigated. Needle biopsies were obtained at rest, after 30 min of circulatory occlusion, and 15 min after the occlusion was released. G-1,6-P2 averaged 75 +/- 8 (SE) mumol/kg dry wt at rest and did not change significantly after occlusion (82 +/- 10; P greater than 0.05) but was slightly elevated after 15 min recovery (88 +/- 12; P less than 0.05 vs. rest). Phosphocreatine (PCr) decreased in all subjects after occlusion (from 80.4 +/- 2.6 to 66.2 +/- 4.7 mmol/kg dry wt; P less than 0.001) and was completely resynthesized after recovery (80.9 +/- 2.4). Fructose 1,6-bisphosphate (F-1,6-P2) was doubled after occlusion (P less than 0.05). During occlusion, the average glycolytic and anaerobic ATP turnover rates were 0.08 +/- 0.02 mmol.kg dry wt-1.min-1 (approximately 4 times the calculated rate at rest) and 0.7 +/- 0.2 mmol.kg dry wt-1.min-1 (less than 20% of the calculated rate at rest), respectively. Total glycolysis was strongly related to the calculated increase in inorganic phosphate (Pi, r = 0.93; P less than 0.01), the decrease in PCr/Cr (reflects an increase in free ADP and AMP) (r = 0.92; P less than 0.01), and the increase in hexosemonophosphates (r = 0.77; P less than 0.05). It is concluded that short-term ischemia in human skeletal muscle results in no change in the content of G-1,6-P2.(ABSTRACT TRUNCATED AT 250 WORDS)