Abstract
Inbred strains of mice excrete all three major urinary proteins (mups) when induced by testosterone, but differ as to the relative proportions and total levels of each mup present. We have now determined the urinary mup pheno-types before and after testosterone treatment of seven recombinant inbred strains derived from progenitor strains exhibiting different mup phenotypes. The results codirm previous observations indicating that total control of mup protein production is a multigenic process. One locus, Mup-a on chromosome 4, determines the relative mup protein proportions after induction by testoster- one. Mup-a, together with other genetic sites, determines the basal mup proportions. Genes other than Mup-a determine the kinetics of mup induction and total mup excretion.