Metabolism of concanavalin A-affinity molecular variants of alpha-fetoprotein in rats

Serum half-lives of unfractionated rat alpha-fetoprotein (AFP), concanavalin A (Con A)-nonreactive AFP, and Con A-reactive AFP in normal 45- to 55-day-old male and female F344 rats were determined to be 19 hours. No significant differences were seen between the half-lives of unfractionated AFP and either of the two Con A-affinity molecular variants of AFP studied. No evidence of interconversion of the Con A-affinity AFP variants during 24 hours in the circulation was found. These results supported the conclusion that the proportions of Con A-affinity molecular variants of AFP in the sera of fetal, newborn, and hematoma-bearing rats result from differences in the relative synthesis rates of the two variants.