Quantification of 11b-Hydroxysteroid Dehydrogenase 1 Kinetics and Pharmacodynamic Effects of Inhibitors in Brain using Mass Spectrometry Imaging and Stable-Isotope Tracers in Mice.

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1; EC 1.1.1.146) generates active glucocorticoid hormones. Small molecule inhibitors have been developed to target 11β-HSD1 for the treatment of dementia; these must enter brain subregions, such as the hippocampus, to be effective. We previously reported mass spectrometry imaging measurement of murine tissue steroids, and deuterated steroid tracer infusion quantification of 11β-HSD1 turnover in humans. Here, these tools are combined to assess tissue pharmacokinetics and pharmacodynamics of an 11β-HSD1 inhibitor that accesses the brain.