To the Editor.
—Halvorsen1 and Feldman et al2 have reported that neurohumoral stimuli resulted in the release of erythropoietin. We recently noted that the number of peripheral reticulocytes increased up to 42% after transnasal administration of 5 mg of gonadorelin acetate and gradually decreased to normal levels (10%) by the end of the next two weeks. Circulating RBC counts increased as well. Four other volunteers were then tested in the same way, and serum erythropoietin levels were measured using a commercial kit. Serum erythropoietin levels increased considerably in three of five tested subjects (Table). Sternalgia was noted in these subjects 30 minutes after gonadorelin inhalation and continued for one week.Our results suggest that gonadorelin may be a potent stimulator for secretion of erythropoietin and may influence erythropoiesis.The regulation of erythropoietin release is influenced by several hormones, such as testosterone, adrenocorticoids, prolactin, growth hormone, and thyroid hormone.