Incorporation of [3H]2-deoxyglucose into glycogen in nervous tissues.

Mice were injected with [3H]2-deoxyglucose and after 1 h high molecular weight glycogen was extracted from brain, liver and muscle tissues. 1-2% of the total radioactivity in each tissue was recovered in the glycogen fraction. Isolated buccal ganglia of the pond snail, Planorbis, and isolated abdominal ganglia of the horse leech Haemopis, were exposed in vitro to [3H]2-deoxyglucose for 1 h. 1-10% of the total radioactivity in these tissues was located in the high molecular weight glycogen fraction. Treatment of the extracted labelled glycogen fractions with amyloglucosidase caused release of the label in a manner consistent with the breakdown of labelled glycogen. Ganglia of snail and leech were exposed to [3H]2-deoxyglucose, fixed in glutaraldehyde and osmium tetroxide solutions, and prepared for autoradiography using aqueous histological processing. Light and electron microscope autoradiography showed that over 90% of the label was positively associated with glycogen particles (alpha- and beta-particles). Certain previously published reports on the incorporation of 2-deoxyglucose into glycogen are discussed in relation to these findings. It is concluded that [3H]2-deoxyglucose is partially incorporated into glycogen in nervous tissue; the labelled 2-deoxyglycogen withstands aqueous histological processing and can be visualized directly by autoradiography.