The metabolism of glucose 1-phosphate and glucose 6-phosphate and their influence on the metabolism of glucose in rat-diaphragm muscle

Abstract

The pattern of metabolism of [C14] glucose 1-phosphate and [C14]glucose 6-phosphate was followed in rat-diaphragm muscle by applying a quantitative radiochromatographic technique. The hexose phosphate esters, like glucose, were converted into glycogen, oliogosaccharides, lactate and COL. With a substrate concentration of 1% (w/v) (calculated as glucose) glycogen synthesis was greater from glucose 1-phosphate than from glucose, whereas the synthesis from glucose 6-phosphate was much less. Lactate formation was about the same from glucose and glucose 6-phosphate, but less from glucose 1-phosphate. CO2 formation was higher from the hexose phosphate esters than from glucose. Insulin had no influence on the metabolism of the hexose phosphate esters. Glucose 6-phosphate (1%) increased glycogen synthesis from [C14] glucose (0-1%) and increased the [C14]glucose concentration in the tissue, in the absence and presence of insulin. These effects were not observed in the presence of lower concentrations (0.01 and 0.1%) of glucose 6-phosphate. Glucose 6-phosphate in concentrations of 0-01, 0.1 and 1% decreased lactate formation from 0.1% [C ]glucose. Glucose 1-phos-phate (1%) only slightly increased glycogen synthesis from [C14]glucose and decreased lactate formation from glucose.