Rittenberg, David

In 1933, Schoenheimer, who was medically qualified and had been working with Aschoff in the Pathology Institute in Freiburg, moved to Columbia University, New York, and was joined the next year by David Rittenberg. Rittenberg had just spent some time in Urey s laboratory in the Rockefeller Institute learning techniques for handling deuterium. Their first experiments concerned the metabolism of deuterated fatty acids in rats and the demonstration (see below) that 2H from heavy water was incorporated by the animals into fatty acids and cholesterol. 

Work on the biosynthesis of cholesterol began in earnest after Rudolf Schoenheimer and David Rittenberg, at Columbia University, developed isotopic tracer techniques for the analysis of biochemical pathways. In 1941, Rittenberg and Konrad Bloch were able to show that deuterium-labeled acetate (C2H, COO ) was a precursor of cholesterol in rats and mice. In 1949, James Bonner and Barbarin Arreguin postulated that three acetates could combine to form a single five-carbon unit called isoprene. 

Q Bloch had to flee as a Jew from the Nazi regime in 1936 via Switzerland to the USA. At Columbia University in New York, he was able to show together with David Rittenberg in 1942, using isotopically labelled acetate, that this was a precursor for the cholesterol synthesis in animals. The polyene cyclisation of the triterpene squalene produces lanosterol, which is degraded to cholesterol, the central intermediate of all human steroids. [350]... 

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