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Abstract: SA-PO1027

Fludrocortisone-Induced Production of Erythropoietin (Epo) in Mouse Kidney Nephron

Session Information

Category: Fluid, Electrolytes, and Acid-Base

  • 702 Water/Urea/Vasopressin, Organic Solutes

Authors

  • Yasuoka, Yukiko, Kitasato University, Sagamihara, Japan
  • Oshima, Tomomi, Kitasato University, Sagamihara, Japan
  • Sato, Yuichi, Kitasato University, Sagamihara, Japan
  • Nonoguchi, Hiroshi, Kitasato University Medical Center, Kitamoto, Saitama, Japan
  • Kawahara, Katsumasa, Dept of Physiol, Kitasato Univ School of Med, Sagamihara, Japan
Background

Under normal conditions, Epo mRNA expression was small but clearly detected in kidney tubules, such as proximal convoluted tubule (PCT), medullary thick ascending limb (MTAL), distal convoluted tubule (DCT) and collecting ducts (CDs). The expression in the peritubular cells was observed only in hypoxic condition (7% O2, 4 hr). (Nagai, Yasuoka, et al, 2014). We investigated the effect of fludrocortisone (an aldosterone receptor agonist) on Epo mRNA in the mouse kidney.

Methods

Fludrocortisone of 2.5 mg/100 g BW was once applied to mice (C57BL/6J, male, 10 weeks) at time 0. Then, Epo, hypoxia-inducible factor 2α (HIF2α) and prolylhydroxylase 2 (PHD2) mRNAs expressions were evaluated at 2, 4, 6 and 72 hr using tyramide-ISH technique.

Results

After the injection, Epo mRNA expression was slightly increased in MTAL, and strongly increased in CCD and outer medullary CD (OMCD). However, it was never detected in the peritubular interstitial cells. The HIF2α mRNA was increased in glomerulus, PCT, TAL, DCT, CCD and OMCD as well as the peritubular cells of both kidney cortex and medulla. The PHD2 mRNA expression was also increased in PCT, TAL, DCT, CCD and OMCD. Epo, HIF2α and PHD2 mRNA expressions were increased in parallel at 4 hr after injection, and decreased to the original level at 72 hr.

Conclusion

Epo mRNA expression is increased only at renal tubule cells by stimulation of fludrocortisone. The regulation of the Epo expression by fludrocortisone is different from that by hypoxic stimulation.