No abstract

Genetic and hormonal factors and their interaction in the regulation of serum insulin level in mice have been examined. The inbred YS/ChWf and VY /Wf strains each segregate into two genotypes which düfer in their mean serum insulin level. YS/ChWf produces yellow AY/a and non-yellowa/a offspring; VY /Wf produces yellow A vy /a and non-yellow a/a young. Serum insulin levels in yellow YS males are lower than in their a/a brothers. However, in yellow VY males, these levels are higher than in a/a VY males. Response of serum insulin concentration to growth of an allogeneic tumor also differs between the two strains. Levels are increased in both VY genotypes while there is no change in the yellow YS mice and a decrease in the non-yellow YS mice. Castration had no effect on the serum insulin concentration in yellow YS males but reduced it to an extremely low value in the non-yellow YS males. Serum insulin levels and their response to growth of aJlogeneic tumor were also studied in several F 1 hybrids between these strains. The data indicate that the YS genome exerts a depressing effect on serum insulin concentration and that this effect is decreased when combined with the VY genome. The A vy /a ge no type seems to induce a higher serum insulin concentration and greater response to tumor growth than the AY /a genotype.Horm. Metab. Res. 2: 68-71 (1970) K e y -W 0 r d s Serum Insulin -Tumor GrowthCastration -Mouse Genotypes