Concanavalin A affinity molecular variants of alpha-fetoprotein in neonatal rat serum and in the serum of rats bearing hepatomas.

Abstract

Summary Two molecular variants of rat serum α-fetoprotein (AFP) based on their reactivity with concanavalin A have been identified previously. A difference between the concanavalin A affinity molecular variant patterns of AFP synthesized by primary and transplantable hepatomas and the pattern synthesized during neonatal growth was demonstrated. The percentage of the total AFP not reactive with concanavalin A remained constant at 42 to 45% from birth through 4 weeks of age in the neonatal rat serum. The percentages of concanavalin A-nonreactive AFP in the sera of rats bearing 3′-methyl-4-dimethylaminoazobenzene-in-duced primary hepatomas varied between 11 and 64% among tumors. The percentages of the total serum AFP not reactive with concanavalin A were determined in the sera of Buffalo rats bearing Morris transplantable hepatomas 7777 and 8994 and in the sera of Fischer and Yoshida rats bearing transplantable 3′-methyl-4-dimethylaminoazobenzene-induced hepatomas. The percentage of the concanavalin A-nonreactive molecular variant was characteristic for each hepatoma line and was independent of the total serum AFP concentration and of the total serum protein concentration. The differences between the pattern of concanavalin A affinity molecular variants of AFP present during newborn life and the patterns present during the growth of primary and transplantable hepatomas indicate that the control of synthesis and/or processing of AFP during these two periods of active AFP production is not the same.