The stability of endogenous corticotrophin in rat blood in vitro

Endogenous corticotrophin is stable in blood in vitro for periods of up to 1 hr. at 4° and 22°, and in plasma for at least 24 hr. at —15°. Estimates of plasma corticotrophin concentration provide less consistent results than assays done on whole blood. The optimal conditions for storing blood prior to the determination of its corticotrophin concentration are discussed.