RE-EVALUATION OF A TECHNIQUE OF PITUITARY INCUBATION IN VITRO AS AN ASSAY FOR CORTICOTROPIN RELEASING FACTOR1

Abstract

The in vitro pituitary incubation system used previously for the characterization of CRF activity has been reinvestigated. Under the conditions as used to assay CRF, there is no detectable destruction of ACTH activity. The effect of CRF cannot therefore be explained on the basis of inhibition of ACTH inactivation. CRF does not act either by potentiating ACTH at the adrenal level or by an inherent adrenocorticotrophic activity. When considering the minimal active dose of purified substances, this test system appears to be highly specific for CRF. There is complete agreement as to characterization of CRF between data obtained in vitro and with recent in vivo assay systems.