An antibody against either human c-myc epitope or human cTnT was used. Western blot analysis of reconstituted muscle fibres from normal rat hearts with antibody against human c-myc epitope (A), from PTU-treated rat hearts with antibody against human c-myc epitope (B) and from normal and PTU-treated rat hearts with antibody against hcTnT (C). A and B, lane identifications are as follows: lane 1, pure recombinant c-myc WT-cTnT; lane 2, muscle fibres reconstituted with c-myc WT-cTnT + cTnI + cTnC; lane 3, muscle fibres reconstituted with c-myc cTnTE162DEL + cTnI + cTnC; lane 4, muscle fibres reconstituted with c-myc cTnTK211DEL + cTnI + cTnC. No immunoreactivity was evident (data not shown) for the endogenous cTnT in reconstituted muscle fibres from both normal and PTU-treated rat cardiac muscle fibres. C, lane 1, pure recombinant cTnT; lane 2, muscle fibres from normal rat heart; lane 3, muscle fibres from PTU-treated rat heart. Lanes 2 and 3 demonstrate that there is only one adult cTnT isoform in these adult rat heart muscle fibres. Typically, Western blot was performed once or twice to detect different forms of cTnT.