The Metabolism of Glycerol by Hypothalamic and Pituitary Tissues in Vitro in the Rat 1

Summary

The metabolism of labeled glycerol in vitro and the activity of glycerol kinase (EC 2.7.1.30) were measured in rat tissues. Although glycerol was actively oxidized and converted to lipids by hypothalamus the rates were low compared to liver and kidney. The activity of anterior pituitary was significantly greater than hypothalamus which was in turn greater than cerebral cortex. After infusion of glycerol-¹⁴C iv label was recovered in phospholipids of brain tissues, direct assay of glycerol kinase provided similar results with the same order of activity among the tissues tested. Because glycerol kinase was present in hypothalamus, it is concluded that glycerol could potentially function as a signal for hypothalamic control systems. Anterior pituitary metabolism of glycerol was sufficiently active to classify glycerol as an energy substrate in this tissue.