Renal and colonic potassium transporters in the pregnant rat

Crystal A. West, Paul A. Welling, David A. West, Richard A. Coleman, Kit Yan Cheng, Chao Chen, Thomas D. Dubose, Jill W. Verlander, Chris Baylis, Michelle L. Gumz

Research output: Contribution to journalArticle

Abstract

Gestational potassium retention, most of which occurs during late pregnancy, is essential for fetal development. The purpose of this study was to examine mechanisms underlying changes in potassium handling by the kidney and colon in pregnancy. We found that potassium intake and renal excretion increased in late pregnancy while fecal potassium excretion remained unchanged and that pregnant rats exhibited net potassium retention. By quantitative PCR we found markedly increased H + -K + -ATPase type 2 (HKA2) mRNA expression in the cortex and outer medullary of late pregnant vs. virgin. Renal outer medullary potassium channel (ROMK) mRNA was unchanged in the cortex, but apical ROMK abundance (by immunofluorescence) was decreased in pregnant vs. virgin in the distal convoluted tubule (DCT) and connecting tubule (CNT). Big potassium-α (BKα) channel-α protein abundance in intercalated cells in the cortex and outer medullary collecting ducts (by immunohistochemistry) fell in late pregnancy. In the distal colon we found increased HKA2 mRNA and protein abundance (Western blot) and decreased BKα protein with no observed changes in mRNA. Therefore, the potassium retention of pregnancy is likely to be due to increased collecting duct potassium reabsorption (via increased HKA2), decreased potassium secretion (via decreased ROMK and BK), as well as increased colonic reabsorption via HKA2.

Original languageEnglish (US)
Pages (from-to)F251-F259
JournalAmerican Journal of Physiology - Renal Physiology
Volume314
Issue number2
DOIs
StatePublished - Feb 2018

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Keywords

  • BK
  • Big potassium channel
  • H -K -ATPase type 2
  • HKA2
  • ROMK
  • Renal outer medullary potassium channel

ASJC Scopus subject areas

  • Physiology
  • Urology

Cite this

West, C. A., Welling, P. A., West, D. A., Coleman, R. A., Cheng, K. Y., Chen, C., Dubose, T. D., Verlander, J. W., Baylis, C., & Gumz, M. L. (2018). Renal and colonic potassium transporters in the pregnant rat. American Journal of Physiology - Renal Physiology, 314(2), F251-F259. https://doi.org/10.1152/ajprenal.00288.2017