Precorticotrophin in Blood

Abstract

THE existence of precorticotrophin, precursor of corticotrophin, has been demonstrated by Dasgupta and Young¹. Extracts of ox anterior pituitary, otherwise inactive, acquire a corticotrophic activity detectable by Sayers' test (adrenal ascorbic acid depletion) when the medium is acidified (pH 3) or when urea (3–8 M) is added to it. These findings have been confirmed by Dixon et al.², who observed the presence of precorticotrophin in pig pituitary also (personal communication). Earlier, Moruzzi et al.³ reported the presence of an ‘inactive’ form of corticotrophin (activable by treatment with oxycellulose) in the blood of patients suffering from various types of adrenal insufficiency, including Addison's disease; they called it ‘activable’ corticotrophin. The possibility that ‘precorticotrophin’ may be comparable with ‘activable’ corticotrophin and that the former may be in circulation even under normal physiological conditions was discussed by Dasgupta⁴. The present report is concerned with the actual demonstration of precorticotrophin in normal rabbit blood.