Paradoxical body and kidney growth in potassium deficiency

F. Fervenza, T. Tsao, R. Rabkin

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

In the growing animal, K deficiency (KD) retards body growth, but paradoxically stimulates renal growth. If KD persists, interstitial infiltrates appear and eventually tubulointerstitial fibrosis develops. In patients with chronic KD, renal cysts may form and with time tubulointerstitial disease with renal failure develops. Since early in KD, kidney IGF-I levels increase and may be a cause of the renal hypertrophy, and as TGF-β promotes hypertrophy and fibrosis, we examined the expression of these growth factors in chronic KD. Rats were given a KD diet or pair or ad-lib fed a normal K diet. After 21 days, KD rats weighed less than pair fed controls, while the kidneys were 49% larger Serum IGF-I and kidney IGF-I protein levels were depressed, as were IGF-I mRNA levels, and is largely attributable to decreased food intake. Kidney IGFBP-1 and TGF-β mRNA levels were increased (p < 0.05). There was marked hypertrophy and adenomatous hyperplasia of outer medullary collecting ducts, hypertrophy of thick ascending limbs of Henle (TALH) and interstitial infiltrates. Both nephron segments stained strongly for IGF-I and IGFBP-1. Only the non-hyperplastic TALH was strongly TGF-β positive. Interstitial infiltrates containing monocytes/macrophages were prominent. These findings are consistent with a sustained role for IGF-I in promoting the renal hypertrophy of KD and appear to be caused by local trapping of IGF-I by the over-expressed IGFBP-1. Localization of TGF-β to the hypertrophied non-hypoplastic tubules containing IGF-I, suggests that TGF-β may be acting to convert the proliferative action of IGF-I into a hypertrophic response. TGF-β may also contribute to the genesis of the tubulointerstitial infiltrate. Finally, the reduced levels of serum IGF-1 levels may be a cause of the blunted body growth.

Original languageEnglish (US)
Pages (from-to)339-346
Number of pages8
JournalRenal Failure
Volume23
Issue number3-4
DOIs
StatePublished - Aug 9 2001

Keywords

  • Body growth
  • Hypokalemia
  • IGF-I
  • IGFBP-1
  • Iinterstitial fibrosis
  • Kidney growth
  • Potassium deficiency
  • TGF-β

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine
  • Nephrology

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