Ultrastructural Autoradiographic Study of the Uptake and Localization of D-Glucose-3H

Abstract

The uptake and localization of D-glucose-6-3H was studied in developing neutrophils from normal human bone marrow by means of ultrastructural autoradiography. Marrow cells were pulse labeled for 30 min in vitro at 37°C with 250 µCi D-glucose-6-3H in phosphate buffer (pH 7.4) containing bone marrow plasma. Autoradiographic data indicated that glucose incorporation in developing neutrophils is a function of maturity and is related to the amount of intracellular glycogen. Developing neutrophils from the myeloblast stage through the early metamyelocyte stage incorporate limited amounts of glucose; however, in concurrence with increased quantities of intracellular glycogen, commencing with the late metamyelocyte stage, neutrophils show a dramatic increase in their capacity to concentrate this sugar. The ability to incorporate large quantities of glucose further increases in the band and segmented neutrophil stages. D-Glucose-3H concentrated in areas of glycogen clustering and occasionally in areas containing small cytoplasmic vesicles that were in close approximation to small clusters of glycogen in late metamyelocytes and band and segmented neutrophils. Specific cellular components, e.g., rough endoplasmic reticulum and Golgi and both formative and definitive primary (azurophil) and secondary (specific) granules, were not preferentially labeled in the promyelocyte and myelocyte stages. Selective glucose-3H labeling also was not observed in the Golgi and formative tertiary granules in the metamyelocyte, band, and young segmented neutrophil stages; primary, secondary, and tertiary granules in these cells were occasionally labeled, but labeled granules were invariably found to be closely associated with glycogen clusters.