Studies on the variation of serum sialic acid and hexosamine contents in the Sprague-Dawley rats with the experimental bone tumor.

Variations of serum sialic acid and total hexosamine ( glucosamine and gala· ctosamine) levels were investigated in rats of the Sprague-Dawley strain for clarification as follows: ( 1) Physiological variations of these levels by age in normal rats. (2) Variations of these levels during the growth of tumor after intramedullar implantation of Walker carcinosarcoma 256; relationship between these values and treatments; and the changes of these values according to the relapse and/or metastasis in the treated rats. As a result, the values of serum sialic acid and of total hexosamine showed a tendency of gradual increase by age. Serum sialic acid and total hexosamine levels and ratio of glucosamine to galactosamine showed significant increase with the growth of the implanted tumor. After treatments these values returned to normal ranges, but these values were elevated again when recurrence and/or metastasis occurred. Therefore, it may be valuable in observing the response to therapy and in prognosis, to determine these values. There were positive correlation coefficients between the wet weight of tumor masses transplanted subcutaneously and the serum levels of sialic acid and also between the levels of serum siaiic acid and total hexosamine in this study. The high contents of total hexosamine were caused to a large extent by the cha!lges of glucosamine contents and to a less extent by the changes of galactosamine levels. Galactosamine, which was found much more than glucosamine in bony tissues, was not released into blood by lesions of the bone substrate.