Abstract
Distribution of the in vivo liver catalase-depressing substance [toxohormone(liver catalase)] in the cells of Rhodamine sarcoma of rats, was examined.
1) Intracellular particles of Rhodamine sarcoma were centrifugally divided into nuclear, mitochondrial, and microsomal fractions. Each of these fractions was individually injectded into mice, and catalase activity was measured with the homogenates of the livers. The in vivo liver catalase-depressing activity was the highest with nuclear fraction. Mitochondrial fraction scarcely showed the activity, while the depressing activity of microsomal fraction varied from one preparation to another. The fractions prepared from tumor tissues freshly obtained had significantly lower activity than those prepared from tumor tissues stored in frozen state. Probably, during the period of storage, particle complexes containing the depressing substance are dissociated into particles of smaller sizes (equivalent in size mostly to microsomes).
2) Nuclear fraction from dorsal muscles of normal rats showed the depressing activity, but not that from the livers.
3) Nuclei isolated from tumor tissues showed the depressing activity. When they were further divided into fractions of chromatins and nucleoli, the former fraction was active, but not the latter fraction.
4) It is concluded that the depressing substance is at least mostly present in the nuclei of the cells of Rhodamine sarcoma and dorsal muscle, localized in the chromatins.
