The $alpha$-glycerophosphate (GP) cycle in dipteran insect flight muscle is composed of two enzyme, the cytoplasmic $alpha$-glycerophosphate dehydregenase ($alpha$GPDH) and the mitochondrial $alpha$-glycerophosphate oxidase ($alpha$GPO). In order to analyze the enzyme activity in transformant, nine strains of Drosophila melanogaster have been constructed to have the flight muscle-specific $alpha$-glycerophosphate dehydrogenase ($alpha$GPDH) cDNA under the control of the Drosophila heat shock promoter (hsp70) on the third chromosome. These strains were compared with $alpha$ GPDH null mutant line in the enzyme activity. All the transgenic strains exhibited higher enzymatic activities than null mutant line, but the amount of activity was still very low even at heat shock condition showing 30% in $alpha$GPDH enzyme amount, compared with wild type.