Is the renal production of erythropoietin controlled by the brain stem?
Although the structure and function of erythropoietin (Epo) are well documented, the mechanisms of the regulation of the renal synthesis of Epo are still poorly understood. Especially, the description of the localization and function of the O(2)-sensitive sensor regulating the renal synthesis of Epo is insufficient. A body of evidence suggests that extrarenal O(2)-sensitive sensors, localized particularly in the brain stem, play an important role in this connection. To support this concept, high cerebral pressure with consecutive hypoxia of the brain stem was generated by insufflation of synthetic cerebrospinal fluid into the catheterized cisterna magna of rats. When the cerebral pressure of the rats was above the level of their mean arterial blood pressure or the high cerebral pressure persisted for a longer period (>/=10 min), the Epo plasma concentration increased significantly. Bilateral nephrectomy or hypophysectomy before initiation of high intracranial pressure abolished this ef
