Quantification of subcellular glycogen in resting human muscle: granule size, number, and location

Single-particle diameter of glycogen granules ranged from 10 to 44 nm in human skeletal muscle biopsies.

• Glycogen granules were found to be more densely concentrated in the subsarcolemmal space compared to the myofibrillar space.
• The single-particle volume of glycogen granules was greater in the myofibrillar space than in the subsarcolemmal area.
• Glycogen particle size and number were quantified with an intra- and interobserver variability generally less than 4%.
• Findings suggest that proglycogen and macroglycogen may not be distinct entities but different forms of glycogen molecules.
• A compartmentalized pattern of glycogen deposition in human skeletal muscle was observed, indicating variations in size and density.

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