Synthesis and biological activity of N-terminal lipidated and/or fluorescently labeled conjugates of astressin as corticotropin releasing factor antagonists.

This report describes the synthesis of eight N-terminally modified astressin analogs and their biochemical evaluation as corticotropin releasing factor (CRF) antagonists. The lipidated astressin derivatives were tested on rat CRF receptor type 1 and 2alpha and were found to be active as CRF antagonists (rCRFR1: pA(2)=7.5-8.3; rCRFR2alpha: pA(2)=7.5-9.0) with nearly equal activities as compared to unmodified astressin (rCRFR1: pA(2)=8.3+/-0.09; rCRFR2alpha: pA(2)=8.7+/-0.08).