Inositol formation by cyclization of glucose chain in rat testis

A homogenate of rat testis capable of incorporating carbon from glucose-U-C 14 into inositol has been described in a previous publication ( Eisenberg and Bolden, 1963). In an attempt to differentiate 1 1 A soluble system which synthesizes inositol-C 14 from glucose-U-C 14 has been found in yeast ( Chen and Charalampous, 1963). between a hexose moiety ( Imai, 1963; Loewus and Kelly, 1962) and hexose fragments ( Charalampous, 1957; Hauser and Finelli, 1963) as precursors of inositol, the conversion of specifically labeled glucose to inositol has now been studied in rat testis homogenate with the aid of a combined plant and chemical degradative system described previously ( Loewus et al , 1962 ). Experimental evidence to be presented in this paper points unequivocally to a pathway of biosynthesis of inositol in the mammal involving cyclization of a six-carbon unit.