[Concordance between vasopressin gene expression and growth of Walker 256 carcinosarcoma in rats]

The growth features of Walker 256 carcinosarcoma in rats of different genotypes were investigated. The experiments has been carried out on rats of the inbred Brattleboro and WAG lines, as well as on their hybrids segregated during congenic translocation of the normal vasopressin gene to the genotype of the Brattleboro rats. Brattleboro rats do not express the vasopressin gene. It has been found that there are only two types of tumor growth dynamics. In rats of the inbred Brattleboro line and in homozygotes di/di, that were segregated by backcrossings of heterozygous offsprings from the original crossbreeding between (WAG x Brattleboro) F1 x Brattleboro and the individuals with parental Brattleboro genotype, having grown to some extent the tumor regresses and disappears. In hybrid heterozygous siblings of di/+ genotype tumor grows linearly with time and always leads to fatal outcome. It has been found that, in the congenic procedure, the tumor regression trait is stably maintained and persistently inherited in lineage concordantly with the di/di genotype and, in rats with at least one allele of a normally expressed vasopressin gene, continuous and lethal tumor growth is always observed.