[Study of histidine decarboxylase activity (HDC) in murine fetal hematopoietic organs. Description of basophil-enriched splenic cell population during fetal life].

The role of histamine in vitro during hematopoiesis has been described by several authors. This work was carried out to determine whether histamine could be available in hemopoietic organs by measuring the HDC activity and the histamine content of developing hemopoietic tissues from C 57 BL/6 mice during fetal life (liver from the 12th day of gestation, spleen from the 14th day, and bone-marrow from the 17th day) and postnatal life. High values were found in the liver, the bone marrow, and especially the spleen between the 17th and the 19th days of gestation. A rapid fall in these values was seen near birth. Interestingly, electron microscopy analysis of day 18 fetal spleen cells, provides evidence for a basophil-rich cell population (25%).