Effect of ascorbic acid and glucoascorbic acid on nucleic acids in tumor tissue.

we described the re tarding effect of the continuous administration of a nontoxic dietary level (1 and @ per cent) of il glucoascorbic acid on Crocker rat carcinoma and mouse adenocarcinoma E 0771. Apparently, the effects resulted from the low ascorbic acid concen tration in blood plasma and tissue induced by the analog. Our present investigation concerns the effect of low ascorbic acid concentrations in tissue on the deoxypentosenucleic acid (DNA) and pen tosenucleic acid (PNA) contents in fibrosarcoma of guinea pig and Crocker rat carcinoma. The total DNA and PNA and the nuclear DNA contents were estimated. Goldstein et at. (7) found that a scorbutogenic diet induced changes in the PNA and DNA contents of the spleen and adrenals of guinea pigs and increased the PNA/DNA ratio. On the basis of their experiments in vifro, with and without ascorbic acid added, they concluded that ascorbic acid is involved in the formation of DNA from PNA. MATERIALS AND METHODS A British brown and white strain of rats, bear ers of Crocker carcinoma, originally obtained from was used for this investigation. Both the control and treated animals, all males of the same age and weight, were kept on an isocaloric Sherman-LaMer scorbutogenic diet. The tumors used for the deter mination of nucleic acids were 0.75†" 1.0 cm. in di ameter, fast-growing, and without any necrotic areas. A transplanted fibrosarcoma, AL-S, origi nally induced by injection of methylcholanthrene in guinea pigs of Family A, obtained from the Jackson Memorial Laboratory, was used for the same determination. The guinea pigs, both treated * Aided by a grant from the Damon Runyon Fund for Cancer Research. and control, were also placed on an isocaloric Sherman-LaMer diet, and the doses of sodium ascorbate, 3, 10, and %5mg/day, were given orally in water solution. The guinea pigs were placed on the Sherman LaMer diet the day before the fibrosarcoma was transplanted. The rats were kept on the same diet 10 days prior to transplantation. D-GlucOascorbic acid was added in the amount of @ per cent to this diet.