The in vitro synthesis and secretion of alkaline phosphatase from first trimester human decidua

We studied the in vitro synthesis and secretion of alkaline phosphatase by human first trimester decidual tissue incubated in organ culture. Decidua synthesizes two different alkaline phosphatase isoenzymes; heat stable and heat labile. decidual tissue maintains a constant pool of alkaline phosphatases. The synthesis of alkaline phosphatase may be the driving force for its secretion. The de novo synthesis and secretion rate of alkaline phosphatases were also investigated. The higher specific radioactivities of the secreted enzymes than those found in the tissue may suggest that newly synthesized alkaline phosphatase is preferentially released. The intracellular distribution of the alkaline phosphatase isoenzymes was compared as well. The characteristics of the two isoenzymes are different in human decidua of maternal origin from those previously reported in the human placenta originating from embryonic stem cells.