Splenic lipofuscinosis in mice.

Autopsy examination of young adult mice revealed a characteristic pigmentation of the anterior splenic pole occurring in a high proportion (8-34 per cent) of three mouse strains and two sublines. Histological studies identified the pigment as lipofuscin and electron microscopy provided supporting evidence. Preliminary results are consistent with the hypothesis that lipofuscin may represent non metabolisable debris from cellular breakdown associated with lysosomal activity.