市川 智彦

In spite of the scrupulous analysis of the karyotypes of blood cells of leukemic patients, researchers have found the cells with abnormal karyotypes in only about a half of the human leukemias (Sandberg, 1980). The concept that leukemias are caused by the malignant transformation of the hematopoietic stem cells is generally accepted. But it is uncertain whether or not the predominantly proliferating cells with normal karyotypes in the leukemias are real descendants of the malignant stem cells. In the course of the study of radiation-induced leukemias in mice we have found a new type of the myeloproliferative disorder in which increased cells in the hematopoietic tissues consisted mainly of normal cells stimulated by the malignant T-lymphoma cells. This study is the report on this new disease which was found in a mouse. © 1987, The Japan Academy. All rights reserved.

Content of androgen receptor, retention of injected testosterone and karyotype of SC 115, androgen-dependent tumor, were compared with those of CS 2, an androgen-independent subline derived from SC 115. Although Bmax was less than that of SC 115, androgen receptor was present in the cytosol and the nuclear extract from CS 2. To examine the ability for androgen retention, a large amount of testosterone was injected into tumor-bearing mice, and the amount of androgen in the crude nuclear and postnuclear fractions of tumors was compared. In both fractions, retention of injected androgen was higher in the SC 115 than in the CS 2. Since most of the injected testosterone was not metabolized in the tissues and the injection of testosterone 5α-reductase inhibitor showed no significant influence on the growth rate of the SC 115, intracellular active androgen was assumed to be testosterone in these tumor cells. As the CS 2 was tetraploid, the androgen independency of the CS 2 seems to be related to chromosomal changes. © 1987, The Japan Endocrine Society. All rights reserved.