A HISTOCHEMICAL STUDY OF INTRANUCLEAR INCLUSIONS IN MOUSE LIVER AND HEPATOMA

Abstract

Intranuclear inclusions which develop in the hepatic cells of mice fed a methionine-rich basal/bentonite diet and inclusions which occur spontaneously in a transplantable hepatoma contain materials of cytoplasmic origin which have become segregated within the nucleus. These materials include sudanophilic lipids, glycogen, iron-containing pigments, and the enzymes acid and alkaline phosphatase, non-specific esterase and β-glucuronidase. In general, their presence in the inclusions varies with their abundance in the cytoplasm. Mitochondria and the succinic dehydrogenase activity associated with them have not been observed within these intranuclear inclusions. Ihe inclusions are always enveloped by a layer of desoxyribonucleic acid which resembles that which lines the nuclear membrane. They arise contiguous to the nuclear membrane and appear to increase in size gradually. Hence, it is possible that the inclusions may represent invaginations of the nuclear membrane in which cytoplasmic materials accumulate. It is also postulated, however, that inclusions could be and may be formed by accumulation of cytoplasmic materials which normally diffuse freely between the swollen chromosomal vesicles of the resting nucleus. The inclusions arise under a great variety of conditions, but they invariably occur in greatly enlarged nuclei. The altered relationship of nuclear surface to nuclear volume may play an important role in the formation of intranuclear inclusions.