Cholestenone, labelled with

Cholestenone, labelled with C , III, 233 Cholesterol, trityl ether, III, 86 Cholic acid, phytochemical reduction of, IV, 92... 

Ring A of cholestenone " as well as of testosterone has been labeled with C by Turner while Heidelberger, Brewer and Dauben have synthesized isotopic 1,2,5,6-dibenzanthracene. 

The relationship of cholesterol to cholestanol has now been delineated. Early experiments of Schoenheimer ef al. (103, 104) and Rosenfeld and Webster (105) resulted in a proposal that cholesterol was metabolized to -cholestenone (XXIX), which was reduced to cholestanol or coprostanol (106) indeed. Baker and Greenberg (106) detected C-cholestanol in rat feces after administration of radioactive acetate. Anker and Bloch (107) and Stokes et al. (108) found efficient conversion of labeled J -cholestenone to tissue cholestanol in rats. Cholesterol was shown (109) to be a precursor of cholestanol in the adrenals, liver, and intestine of guinea pigs. With cholesterol-4- - C-4/3- H Werbin et al. showed that the cholestanol isolated from the adrenals contained as much as 14% of the tritium at positions 5 and 6, whereas the cholestanol obtained from liver and intestine was virtually devoid of tritium at these positions (110). Based on these observations they proposed the following possible pathway ... 

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