Riboflavin Determinations on Normal Liver and Liver Tumor

Abstract

It was decided to use a fluorometric method in making quantitative estimations of riboflavin from fresh liver tissue after several checks had been run against the Snell and Strong method.∗ The fluorometric method here used is first to determine the total fluorescence, then eliminate the riboflavin by raising the alkalinity to pH 11 and determining the “interfering” fluorescence. The difference between these two values gives the approximate riboflavin value. The fluorescence was measured with a photocell using suitable optical filters.

Liver tumors from Osborn-Mendel rats which had been fed 2-amino 5-azo toluene for a long period were used. These animals were kindly put at our disposal by Dr. E. Emmart. Samples of liver which had been perfused with saline were ground with n/10 HC1, autoclaved for 15 min. and clarified by precipitation at pH 5-6, followed by filtering through No. 42 paper. Recovery of added riboflavin was about 97% by this fluorometric method.

Some of the material was given a short low temperature drying by the lyophile process eliminating most of the water. The data in the tables indicate that the difference between normal and tumor liver is not due to water content.

Comparisons were made between normal livers from normal rats, nontumor bearing liver from dye-fed rats, liver tumors from dye-fed rats, residual liver from which the tumor had been excised, fetal liver, and leg muscle. In the case of a general riboflavin deficiency it would be expected that lower riboflavin values for the muscle would be obtained. A value of 1.4 γ is reported 1 for adult rat muscle on a deficient diet.

In the absence of any other criteria the estimation of “malignancy” was based solely on histologic grounds. The term hepatoma was used to denote growths which reproduced the normal liver structure so closely that there was no histologic indication of “malignancy”.