Carbohydrate Metabolism of Chick Fibroblasts in Vitro

1. The glucose consumption of osteoblasts growing in a medium of plasma and embryo juice has been compared with that of the same cells in plasma and Tyrode medium. Embryo juice causes an initial increased glucose consumption which later falls below the level characteristic of a Tyrode-plasma medium. 2. A modification of a method of measuring the nucleoprotein phosphorus content of tissue cultures is described and among other data obtained the changes which occur in this figure have been noted for fourth passage chick osteoblast cultures and for fresh heart explants during the first 4 days of culture in media of plasma and Tyrode and of plasma and embryo juice. 3. The figures for nucleoprotein content have been correlated with those for glucose consumption and lactic acid production and pronounced differences have been observed in the behaviour of the two types of tissue. The possible significance of the findings is discussed. 4. There is no absolute correlation between high growth rate and high sugar consumption or lactic acid production. 5. The data discussed are consistent with the idea that an increased protein metabolism, and a decreased carbohydrate metabolism result from the addition of embryo juice to osteoblast cultures. Embryo juice has no detectable effects on the carbohydrate metabolism of fresh heart cultures.