THE METABOLISM OF GLUCOSE IN SKIN MAINTAINED IN TISSUE CULTURE

SUMMARY.— The amount of 14CO2 produced from carbon-14-labelled glucose by cultures of adult mouse skin has been measured. By comparing the recovery of radioactivity in 14CO2 using glucose-1-14C as a substrate with the recovery of activity in 14CO2 using glucose-6-14C as substrate, an estimation of the amount of glucose oxidized through the Krebs cycle and the pentose phosphate shunt was made. Approximately 1–6% of the glucose used was oxidized via the Krebs cycle, whereas 3–5–40% of the glucose passed through the pentose phosphate cycle. The addition of phenazine methosulphate (PMS) to the culture medium increased the 14CO2 output by mouse skin cultures by over 100%. Although PMS increased the rate at which glucose was oxidized through the Krebs cycle the greatest effect was on the pentose phosphate shunt, increasing the amount of glucose metabolized by this pathway to 30% of the total. Treatment of cultures with PMS was found to inhibit lipid synthesis almost completely.