The discovery and pharmacological evaluation of potent, selective, and orally bioavailable growth hormone secretagogue receptor (GHS-R) antagonists are reported. Previously, 2, 4- diaminopyrimidine-based GHS-R antagonists reported from our laboratories have been shown to be dihydrofolate reductase (DHFR) inhibitors. By comparing the X-ray crystal structure of DHFR docked with our GHS-R antagonists and GHS-R modeling, we ...