NUCLEIC ACTD METABOLISM IN INTESTINAL MUCOSA: IV. THE EFFECT OF GLUCOSE ON INCORPORATION OF C14-FORMATE INTO PURINES AND PYRIMIDINES IN VITRO

Slices of rat intestine were incubated in Krebs–Ringer phosphate buffer in the presence of C14-formate. The addition of glucose to the buffer stimulated the incorporation of radioactivity into the purines and, in some instances, the pyrimidines of the acid-soluble fraction and nucleic acids of the tissue. With Ehrlich ascites tumor cells studied under similar conditions, the increase in uptake of C14-formate into the purines was somewhat greater. The data suggest also that maximal stimulation with slices of intestine is obtained at glucose concentrations somewhat higher than that required with Ehrlich ascites tumor cells. A finding of interest was the increased incorporation of C14-formate into the thymine of the intestinal DNA in the presence of glucose. This result has not been observed with Ehrlich ascites tumor cells. Slices of rat intestine incubated for 2 hours in the presence of glucose had a higher content of RNA and DNA than tissue not exposed to added glucose.