Alkaline Phosphatase in Cell Cultures of Human Origin

Abstract

IN an attempt to define some of the changes which cells undergo in adaptation to growth in vitro, work has been carried out on the metabolic and enzymatic activities of a variety of established cell cultures, mainly of human origin. For this work, cells were cultured in several media, including Eagle's medium¹ and M199² containing 10 or 15 per cent undialysed human serum, or in a nutrient medium described by Marcus et al. ³ containing 20 per cent undialysed human serum. Cells were grown for 6–8 days on glass surfaces at 37° C. in an atmosphere of 5 per cent carbon dioxide in air, and dispersed with 0.05 per cent trypsin in saline. They were collected by centrifugation at 500g, washed and resuspended in 0.25 M sucrose, and disrupted with a 10-kc./s. Raytheon sonic oscillator for 1–5 min. Cell protein was measured by the procedure of Lowry et al. ⁴.