EFFECT OF CULTURE FROM THE ZYGOTE STAGE ON THE METABOLISM OF GLUCOSE AND GLUTAMINE BY 2-CELL EMBRYOS AND BLASTOCYSTS RECOVERED FROM OUTBREDOR F1-HYBRID FEMALE MICE

The oxidation and incorporation of glucose and glutamine by embryos de rived from cultured zygotes was compared with the utilization of these substrates by embryos recovered directly from the reproductive tract of pregnant females. The oxidation of glutamine was greater at the bla stocyst stage than at the 2-cell stage. Embryos derived from outbred f emales (Qs) were less active in the oxidation of glutamine than those from hybrid (B10D2F(1)) females and development in culture was detrime ntal to this oxidation, especially in blastocysts from the outbred sto ck. The oxidation of glutamine was stimulated by the presence of gluco se at the 2-cell stage but reduced by its presence at the blastocyst s tage. Maternal genotype had no effect on the oxidation of glucose at e ither the 2-cell or blastocyst stage, and only at the blastocyst stage was there evidence of a detrimental effect of culture. The oxidation of glucose was stimulated by the presence of glutamine at the 2-cell s tage but depressed by its addition at the blastocyst stage. Incorporat ion of glutamine increased with development, but this was reduced at t he blastocyst stage by development in culture, especially if the blast ocysts were derived from outbred females. Incorporation of glucose als o increased with development. At the 2-cell stage, culture reduced inc orporation of this substrate, especially into the acid-soluble fractio n of embryos from outbred females. In blastocysts, incorporation of gl ucose into the acid-insoluble fraction was depressed by culture and in embryos from outbred females. In contrast to glucose oxidation, incor poration of glucose into the acid-soluble fraction was reduced by the addition of glutamine at the 2-cell stage but increased by its additio n at the blastocyst stage.