Purpose of review: This article is intended to briefly overview available methodological approaches for the study of regional metabolism in man in vivo, and to summarize recent advances in this field of research.

Recent findings: Several methods have been developed and currently allow for the qualitative and quantitative assessment of energy interconversions and substrate fluxes across individual tissues of man, including the measurement of arteriovenous concentration differences, microdialysis, and nuclear magnetic resonance spectroscopy of carbon, hydrogen, and phosphorus isotopes. Each method alone has been used rather extensively to examine certain aspects of organ and tissue metabolism under a variety of experimental conditions, and has contributed novel information in this regard. The most exciting development appears to be the combined use of more than one investigational technique, across one or more tissues simultaneously. A handful of recent studies have employed complex experimental designs or hybrid methodologies, ultimately demonstrating the potential for a more detailed assessment of metabolism at the local level.

Summary: Clearly, advances in the use, performance, and applications of available methods are expected to provide improved and more powerful tools for the metabolic investigation of organs and tissues in humans in vivo.