Abstract
We have previously reported(1) that concentrations of serum-bound carbohydrates were not elevated in animals bearing intramuscular transplants of the Jensen sarcoma and Walker 256 carcinoma. This was contrary to the general findings in tumor hosts (2). When a bacterial infection was present in the tumor or a bacterial endotoxin was injected into normal animals, however, the serum-bound carbohydrate concentration was elevated. These studies have now been extended by determining the extent of glucosamine-C14 incorporation into serum and hepatic proteins of control, tumor-bearing, and endotoxin-treated rats.
Materials and methods. The bacteria-free tumors(1) were carried as intramuscular transplants in the rectus jemoris muscle of female Holtzman rats for 7 days. Control and experimental rats were selected of the same age and lot and were fed ad libitum. E. coli endotoxin (Difco), suspended to contain 100 μg/1.0 ml, was injected intraperitoneally 24 hours prior to experimentation. Glucosamine-1-C14 (50 μc/mg, Isotopes, Inc.) at a level of 5.0 μc/0.2 ml was injected into the femoral vein 30, 60, and 120 minutes prior to sacrifice. The animals were anesthetized with Na seconal and bled by cardiac puncture. One aliquot of blood (2.5 ml)was mixed with an equal volume of saline containing 0.01 M EDTA, and the mixture centrifuged at 2500 rpm in a clinical centrifuge for 20 minutes to obtain a red blood cell volume and a plasma fraction. The percent plasma volume of whole blood was calculated from these values. The diluted plasma was fractionated by precipitation with TCA, defatted, and dried using the methods described by Robinson et al(3). The residues were dissolved in 5.0 ml of 0.2 N NaOH with warming. Aliquots were taken for protein and C14 assays and for hexosamine isolation. Hexosamine was isolated, after acid hydroylsis, by the Dowex 50 column technique and assayed for hexosamine(3)and for C14 activity.
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