A comparison of human leukocyte phosphatase activity toward sodium beta-glycerophosphate, adenosine 5'-phosphate and glucose 1-phosphate.

F OR A NUMBER OF YEARS this laboratory has been interested in the phosphatase activity of isolated human leukocytes and the marked lability of leukocyte alkaline phosphatase in disease.1 3 Leukocyte alkaline phosphatase has been demonstrated to be essentially limited to the granulocytic cells and to be characteristically low in chronic myelocytic leukemia. Elevated values are noted in polycythemia vera when leukemoid features are present and in many, though not all, cases of idiopathic metaplastic disease resembling chronic myelocytic ‘ Moreover, leukocyte alkaline phosphatase may be increased many fold on a per cell basis in a variety of “stressfull” conditions such as acute pyogenic infection, trauma, hemorrhage, myocardial infarction, etc.3 Similarly, a well-marked elevation in unit cell alkaline phosphatase may be induced over a 72-hour period by the administration of large doses of ACTH or 17-OH corticosteroids to normal subjects. This pattern of response is absent or diminished greatly in chronic myelocytic leukemia. The above experiments have been largely conducted employing sodium f3-glycerophosphate as substrate. The experiments documented below attempt to define leukocyte phosphatase activity in terms of ability to hydrolyze two important physiologic metabolites, the monoesters adenosine 5’-phosphate and glucose 1-phosphate. Adenosine 5’-phosphatase has been demonstrated in various tissimes by Reis4 and in blood serum by Dixon and Purdom. In 1952, Swenseid, \Vright and Bethell#{176} studied the ability of human leukocytes from leukemic subjects to hydrolyze adenosine 5’-phosphate. Utilizing this substrate, they found phosphatase activity in cell populations from subjects with chronic lymphocytic and chronic myelocytic leukemias. Maximal activity was present in the acid pH range, and the conclusion was drawn that adenosine 5’-phosphatase was predominately an acid phosphatase in human leukocytes. It was not realized at the time how labile leukocyte alkaline phosphatase may be, and that values obtained in leukemic leukocytes cannot, because of inherently different metabolic patterns, be extrapolated to nonleimkemic letmkocytes from either normal subjects or subjects with other diseases. The data reported below have been obtained with the following objectives in mind: (1) to reassess the ability of human leukocytes to hydrolyze phos-