Glucose and fatty-acid metabolism in rat bone-marrow cells during accelerated hematopoiesis

The blood supply to the hematopoietic bone marrow is increased during accelerated erythropoiesis or granulopoiesis. Sympathetic vasomotor innervation of the marrow vessels apparently plays no regulatory role here. Possibly, the marrow vascular tone reflects the needs for gas exchange, nutrition, and disposal, which are related to the marrow metabolism. However, there are few relevant studies of carbohydrate and fatty-acid metabolism in normal bone marrow as well as during increased hematopoietic activity. Thus, we studied glucose uptake in vivo, and oxygen consumption, palmitic-acid and glucose metabolism in vitro in bone-marrow cells of awake rats stimulated in vivo with either erythropoietin or granulocyte colony-stimulating factor. During stimulation with either of these two cytokines the marrow glucose uptake and oxygen consumption were approximately doubled. Cellular uptake of palmitic acid and the subsequent oxidation to acid-soluble products and carbon dioxide, and incorporation into lipids, remained constant. When present in excess, palmitic acid depressed glucose-derived carbon dioxide release in cells from both stimulated rats and from controls. Both palmitic acid and glucose appear to be important nutrients in bone marrow with increased erythropoietic or granulopoietic activity. The autonomous innervation of the marrow cells had no apparent influence on either glucose or palmitic-acid metabolism.