[Ontogenesis of the renin system. Implication of this system in hematopoiesis].

The role of the renin-angiotensin system was previously thought to be restricted to the cardiovascular system. It now appears that this system also plays an important role during development, and especially in hematopoiesis. The different elements of the renin-angiotensin system are expressed early during embryogenesis. The renin system plays a role at different steps of hematopoiesis, notably during the first wave of hematopoiesis in the chick embryo system (primitive hematopoiesis), and during the adult phase of hematopoiesis in the fetus (definitive hematopoiesis). In addition, this system is involved in hematopoiesis following experimental irradiation of mice: renin system antagonists improve hematopoiesis in this situation.