Porphyrin concentration and myeloperoxydase activity in the tissues of the Shay chloroma of the rat.

BSERVATIONS on human chloroleukemic tissue have shown that it contains porphyrin, which accounts for its red fluorescence in Wood’s light1 and an enzyme, myeloperoxydase (or verdoperoxydase), to which the green color of the chloroleukemic tissue is due.2 In recent years many chloroleukemic tumors have been described in animals where the tumor tissue also contained porphyrin and myeloperoxydase.3’6 A detailed study of the porphyrin and myeloperoxydase of chloroleukemic tissues in the rat has been made by Schultz et al.7’9 and in the mouse by Loeb et al.3,4 Their investigations corroborate the data obtained from human chloroleukemic tissues, and it now seems obvious that the chloroleukemic tissues of man as well as of animals contain porphyrin and myeloperoxydase. In a previous study1#{176} made on the Shay chioroma of the rat5 we observed that by varying the route of administration (subcutaneous, intraperitoneal and intravenous) and the age group of ‘the inoculated animal (newborn, infantile and adult) various types of chloroleukemic and leukemic processes could be induced, which showed differences in their growth properties, their fluorescence in Wood’s light (porphyrin) and in their green color (myeloperoxydase). Based on these differences the following types may be distinguished: (1) Regressive solitary subcutaneous chloromas, (2) progressive solitary subcutaneous chloromas, (3) disseminated chloromas, and a (4) leukemic form. In table 1 the particulars of transplantation (site of inoculation and age of animals) by which these forms can he obtained, as ve!l as the most characteristic features of these forms, are given. In spite of their great differences in appearance, we suggested that these various forms were only variations of the same disease developing as a result of changes in the environmental conditions of the transferred cells. In the present study the porphyrin concentration and myeloperoxydase activity of the tissues of these various forms of chloromatous and leukemic processes were determined by quantitative methods. A correlation between porphyrin concentration and myeloperoxydase activity was found to exist, viz. in chloroleukemic tissues with a slow rate of growth, high porphyrin concentration and low myeloperoxydase activity were observed, while in fast growing tissues the reverse was true.