Transformations in the D ring of estrogens by mammalian blood ‘in vitro’.

Investigations of the participation of non-endocrine organs in steroid transformations are gaining equal prominence with those studies in which end products of overall steroid metabolism are sought in the excretia. Although the liver probably plays an important role in this regard, the importance of extrahepatic tissues in steroid metabolism is becoming increasingly apparent. In 1948 Werthessen and collaborators (1, 2, 3) reported that incubation of estrone in blood resulted in destruction of the 17-keto function of the steroid accompanied by a loss of biological activity. On the other hand, Bischoff and associates (4, 5) incubated the red cells of rabbit or man with estrone and observed a marked increase in the biological activity of the added steroid. The discrepancy in the two sets of data was ascribed at the time to differences either in assay techniques or in experimental conditions

Incorporation of purine precursors into tumour cells.

It is undoubtedly of considerable significance that purines occur in every living source which has been examined. The purines are integral parts not only of all the nucleic acids studied, whether of true cellular origin or in the less specialized structures, the viruses, but they are also essential constituents of coenzymes, adenosine-5' -triphosphate (ATP), etc. [...