Uptake of ³H-glucosamine by Osteoclasts

Abstract

PREVIOUS work has shown^1,2 that labelled glucosamine injected intraperitoneally is incorporated very efficiently into the glycoproteins of liver and serum. The glucosamine seems to be utilized intact and this makes it an excellent precursor for a study of the synthesis of muco-substances. In the course of an autoradiographic investigation of these substances in bone using tritiated glucosamine, an unexpected finding was the appearance of the radioactive label in the osteoclast. Furthermore, the distribution of the labelled material with time after injection suggested that the glucosamine was being used by the osteoclast in the synthesis of some component which was involved in bone resorption. Here we describe the autoradiographic distribution with time, of the labelled material found associated with osteoclasts and the resorbing bone surface. Its pattern is unique, and it may well turn out to be an important precursor for studying bone resorption.