Published online by Cambridge University Press: 14 April 2009
G6PD measurements (expressed per g haemoglobin) in both males and females of the parental lines C57BL/6J and C57L/J and four recombinant inbred (RI) lines between them showed segregation of G6PD levels as parental classes (one line showed the higher C57BL/6J activity, three lines were indistinguishable from C57L/J). Haemoglobin also varied significantly among the parental and RI lines but this variation did not explain the variation in G6PD. NADP levels (expressed per g wet wt of erythrocytes) correlated with G6PD levels but one RI line was intermediate in males while two RI lines were lower than either parental line in females. Thus, the major autosomal locus affecting G6PD levels which segregates between these two inbred lines probably does not act directly on NADP levels. The variation in the G6PD levels in the four RI lines co-segregated with the brown coat color locus but the association is not significant because of the small number of RI lines available.