Demonstration of immunoreactive erythropoietin in granular convoluted tubule of mice submandibular gland

Abstract

Extrarenal immunoreactive erythropoietin (Ep) production was immunohistochemically examined in granular convoluted tubule (GCT) of mice submandibular glands using combined treatments of hemolytic anemia (HA) by phenylhydrazine injection, hypoxic stimulation (HYP), and bilateral nephrectomy (BN), with normal and polycythemic mice. The effects of supplementary testosterone administration (TP) to Ep production in GCT were also studied.
In mice with HA and HYP, GCT cells histologically showed marked atrophy, and secretory granules decreased in those GCT cells localized at the luminal side, whereas no atrophy was found in BN mice.
The Ep staining in GCT of the normal and polycythemic mice was negative, and also not clearly in only HYP or BN treatment.
On conditions of the combined treatments with HA, HYP and BN, Ep staining was existed in GCT cells, and its reaction product was stronger in the male than the female. On TP after HA, hypertrophy and increase of secretory granules were not found in GCT compared with TP only, however strong Ep reaction was noted in combined conditions with HYP and BN.
These results suggest that GCT cells of mice might have potentiality for production or accumulation of extrarenal Ep. Target cells of the male hormones GCT cells possibly may play important biological roles for production, accumulation and reabsorption of Ep.