Notes on the irradiation of ergosterol

Abstract

The experiment recorded was in search of possible means of isolating vitamin D. When a 0.1% solution of ergosterol in alcohol or ether is irradiated at room temp., products showing an antirachitic activity and specific absorption are present to a small extent after 30 sec. irradiation, and to a marked extent after 1 min. irradiation. After 10 min. irradiation both properties are increased to about 10 times the former values. Irradiation for periods between 10 and 60 min. increases both properties somewhat further, to about 2-4 times their value after 10 min. irradiation. Thus there is evidence that both antirachitic activity and absorption are produced at approximately the same rate, and that both begin in the earliest stages. If the products of irradiation after removal of ergosterol are exposed to ultra-violet light, both antirachitic activity and absorption decrease, and both disappear almost entirely after 3-5 hrs''. irradiation. The authors have not yet succeeded in obtaining a product showing antirachitic activity without the type of absorption described, or vice versa.