The relationship between erythropoietin production and the juxtaglomerular (JG) cells of the kidney were studied using Harada’s method for staining and Hartroft’s method for estimating JG granularity.
In stimulated erythropoiesis (after bleeding and phenylhydrazine injection), the JG cells also showed hypergranularity. In depressed erythropoiesis, on the contrary, the JG cells showed hypogranularity. Furthermore, from the observation of the chronological change of the JG cell, granularity tended to change in parallel with erythropoietin production. This study gave an indirect evidence of the secretion of erythropoietin by juxtaglomerular cells of the kidney.