Indiana University Medical Center located on the campus of Indiana University-Purdue University at Indianapolis (IUPUI), is a major medical center with large and productive departments in the medical and health related sciences. A number of research programs at this center, largely supported by NIH funds are dependent on isotope ratio mass spectrometry for their research. In order to support these research programs and to enhance the overall research capability of the medical center and IUPUI, a mass spectrometry core laboratory (MSCL) has recently been established through a combination of university and private corporation funds to provide a centralized and complete research support for human and animal metabolic studies. At present, MSCL is equipped with two gas chromatograph mass spectrometers, and provides mass spectrometry support four NIH funded investigators. However, this research facility is presently lacking an isotope ratio mass spectrometer. There is no such instrument on the IUPUI campus; the only isotope ratio mass spectrometers within the Indiana University system are located on the Indiana University-Bloomington campus (50 miles south of Indianapolis) within the department of geology, and are heavily utilized for geochemical analyses. We therefore request funding for the purchase of an isotope ratio mass spectrometer, essential to current and future research programs in human and animal metabolism at the Indiana University Medical Center. Access to an isotope ratio mass spectrometer on the IUPUI campus will greatly facilitate existing NIH supported research which relies heavily on such isotope ratio mass spectrometry determinations and will enhance significantly the biomedical research capabilities of the medical center and affiliated institutions.