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Renal potassium handling in the pregnant rat (892.13)
Author(s) -
West Crystal,
Baylis Chris,
Gumz Michelle
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.892.13
Subject(s) - reabsorption , nephron , aldosterone , endocrinology , medicine , renal sodium reabsorption , potassium , kidney , fetus , chemistry , medulla , homeostasis , potassium channel , gestation , renal cortex , pregnancy , biology , genetics , organic chemistry
The fetus requires a large amount of potassium for normal development. To accommodate this need the normal pregnant rat accumulates ~6.3 mEq of potassium over the course of gestation, over 70% of which is retained during late pregnancy. However, the mechanism of potassium retention during pregnancy is largely unknown. The purpose of this study was to examine the mechanism permitting increased potassium reabsorption in the setting of high circulating aldosterone and enhanced distal nephron sodium reabsorption in the pregnant rat. Recent work on the WNK kinases has provided interesting targets for divergent modulation of sodium and potassium handling in the distal nephron. We measured the mRNA expression of WNK1, WNK3, WNK4, and ROMK in the renal cortex and outer medulla of virgin (V, n=5), mid pregnant (MP, n=5), and late pregnant (LP, n=7) rats using quantitative real‐time PCR. We found increased WNK3 expression in the outer medulla of LP rats compared to V (156 ±15 vs 100±10 % Control). The expression level of the other genes tested did not appear to differ with pregnancy state in either the cortex or the outer medulla. ROMK is the major potassium secretory channel and WNK3 is an inhibitor of ROMK activity. Therefore, the potassium retention of late pregnancy could be due in part to increased outer medullary WNK 3 expression as well as a failure of the expected aldosterone mediated transcriptional increase in ROMK.