Production of Tumours in Mice by Deoxycholic Acid

Abstract

J. W. COOK¹ pointed out that the sterols and bile acids contain in their molecules condensed carbon-ring systems to which are attached a side-chain in such a position that a new 6-membered ring can be formed so as to give the 1: 2-benzanthracene ring system without molecular rearrangement or group migration. The bile acids of the higher vertebrates are all mono-, di-, or tri-hydroxy derivatives of cholanic acid, which compound can be obtained in vitrofrom sterols by degradation, and the principal bile acids bear the names of lithocholic acid (3-hydroxy-cholanic acid), deoxycholic acid (3: 12-dihydroxy-cholanic acid) and cholic acid (3: 7: 12-trihydroxy-cholanic acid). J. W. Cook and G. A. D. Haslewood in 1934² showed that, in the formation of dehydronor-cholene from deoxycholic acid by the procedure of Wieland, such a ring-closure to the 1: 2-benzanthra-cene ring system had actually occurred. Dehydronor-cholene gave on dehyclrogenation the benzanthracene hydrocarbon methylcholanthrene, which was found to be strongly carcinogenic. Afterwards, Fieser and Newman³ showed that methylcholanthrene could be obtained also from cholic acid, which is the chief acid of human bile, and the parent hydrocarbon cholanthrene was synthesized by J. W. Cook, G. A. D. Haslewood and A. M. Robinson⁴ and shown to be carcinogenic.