Chemical Analyses of Sera Influencing Neoplastic Transformation In Vitro

Abstract

Several types of serum that influence “spenteneous” neoplastic transformation of mouse cells in vitro were analyzed for certain constituents. Because the low molecular-weight fraction of gelding horse serum appears to accelerate neoplastic conversion, gelding horse serum was tested for possible contamination with low molecular-weight chlorinated hydrocarbon insecticides, lead, and mercury. Contamination was negligible. Fetal bovine serum, which appears to inhibit neoplastic transformation, was compared with horse and calf serum with respect to certain hormones, 2 enzymes, and 16 elements. Fetal bovine serum differed from the other sera particularly in having high hexosaminidase and galactosidase activities, increased levels of zinc, iron, potassium, phosphorus, and magnesium, and a decreased amount of copper. Mare serum like fetal bovine serum may inhibit transformation as compared with the 2 male sera, gelding and stallion. A comparison of individual pooled samples of mare and stallion with gelding horse sera with respect to 14 elements revealed no distinctive differences except in iron content. Heating fetal bovine and gelding sera to 56° C. for 30 minutes did not destroy the factors influencing neoplastic transformation.