THE EFFECTS OF INDUCED HYPERTHYROIDISM AND VITAMIN B12 ON THE SYNTHESIS OF SOME PHOSPHATE FRACTIONS IN THE RAT LIVER

THE influence of thyrotoxic agents on the turnover of labelled phosphate in various organic compounds of the adult rat liver has been demonstrated by several workers (Flock, Bollman and Berkson, 1948; Fraenkel-Conrat and Li, 1949; Venkataraman, et al., 1950). These in vivo studies, in general, indicate that the thyrotoxic animals have a tendency toward an increased turnover of phosphates in organic linkage. Similar observations have been recorded with intact tissue slices of thyrotoxic rats under conditions of aerobic glycolysis (Goldstein, 1952). Recently, vitamin B12 has been shown to counteract the retardation of growth in young rats which results from administering toxic amounts of trryroid powder or thyroprotein (Betheil and Lardy, 1948; Nichol, Dietrich, Cravens and Elvehjem, 1949; Emerson, 1949; Meites, 1950). Other B vitamins which prevent weight loss in the hyperthyroid mature rat (Drill, Overman and Leathern, 1943) are ineffective in this respect in the immature hyperthyroid rat (Ershoff, 1947).