We recently examined the expression of PPAR-γ in normal lung tissues by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemistry.2By using RT-PCR, we detected the expression of PPAR-γ messenger RNA in two of three normal lung tissues. By Western blot analysis, we detected the expression of PPAR-γ protein in three of five normal lung tissues. Immunohistochemistry demonstrated that PPAR-γ expression was detected in four of six normal lung tissues. In addition, we graded the intensity and extent of expression of immunoreactive PPAR-γ for each tissue specimen on a scale of 0 to 4 according to the grading methodology previously described.3 As a result, immunoreactive PPAR-γ was weakly expressed in bronchial epithelial cells, type I pneumocytes, and vascular endothelial cells (mean ± SD immunohistologic scores were 1.0 ± 0.3, 1.2 ± 0.4, 0.8 ± 0.3, respectively). However, we found the moderate expression of immunoreactive PPAR-γ in type II pneumocytes (mean immunohistologic score was 1.8 ± 0.6), suggesting that type II pneumocytes may be target cells in which PPAR-γ is activated by TZD.