抄録
Electron microscopic observation of Harding-Passey mouse melanoma revealed that melanoma consisted of melanocyte, melanophage, and the third-type cell. The third-type cell appeared to possess two functions; melanosome production and containing melanosomes in the form of melanosome complex. Since the melanosome complex is though t to be a kind of phagosome, it is assumed that, in melanoma, melanocyte per se alters to the third-type cell producing autophagosome; melanosome complex as it becomes old. Lysosomal enzyme activities of melanoma were found to be distributed among the supernatant, microsome, and mitochondrial fractions. The latency of lysosomal enzymes of melanoma was investigated. The cathepsin activity increased by deoxycholate treatment and under the hypotonic condition, but the acid phosphatase activity showed no latency. The relation between melanoma growth and lysosomal enzyme activities was investigated. All enzyme activities determined showed roughly parallel increase with the tumor growth up to the certain stage, and then the cathepsin activity fell down at the late stage, and that of tyrosinase and succinic dehydrogenase also decrease. The acid phosphatase activity, on the other hand, was rather steady. Necrosis of the melanoma at the late stage might not only be due to the lysosomal activities in the third-type cells but to the general deterioration of activity in tumor tissue.
