Gingiva homogenates from the healthy, gingivitis and periodontitis groups all generated Ang II, Ang 1–9 and Ang 1–7 when incubated with a precursor (Ang I or Ang II) as determined by HPLC (Fig 3B to 3E), indicating that ACE, ACE-2, and other enzymes that form Ang II were present and functional. This evidence concerns the gene AGT and periodontitis.