Dietary salt modulates renal production of transforming growth factor-beta in rats

Am J Physiol. 1998 Apr;274(4):F635-41. doi: 10.1152/ajprenal.1998.274.4.F635.


Transforming growth factors (TGF) are potent multifunctional polypeptides that are involved in renal function and glomerular sclerosis. We postulated that dietary salt modified renal production of TGF-beta. An increase in dietary salt produced sustained increases in steady-state levels of mRNA for TGF-beta 1, -beta 2, and -beta 3 in the rat kidney. While serum concentration of TGF-beta 1 did not change, the 8.0% NaCl diet increased urinary excretion of TGF-beta 1, indicating enhanced renal production was the source of TGF-beta 1. Increasing urinary flow rates with diuretics did not further increase synthesis of TGF-beta 1 in animals receiving the 8.0% NaCl diet. The 8.0% NaCl diet increased production of TGF-beta 1 in both glomeruli and tubules, although active TGF-beta 1 was secreted in greater amounts only from glomeruli. Enhanced glomerular production of both inactive and active TGF-beta 1 induced by the 8.0% NaCl diet was inhibited by tetraethylammonium (TEA) and not glybenclamide. Cardiac production of TGF-beta 1 also increased on the 8.0% NaCl diet but was not affected by TEA. The results demonstrated that increased dietary salt augmented glomerular TGF-beta production by a mechanism that included a TEA-sensitive potassium channel. Dietary salt, by facilitating glomerular expression of TGF-beta, may directly promote development of glomerulosclerosis.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Diet
  • Kidney / metabolism*
  • Male
  • Myocardium / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sodium Chloride / administration & dosage*
  • Sodium Chloride / pharmacology
  • Tetraethylammonium / pharmacology
  • Tissue Distribution
  • Transforming Growth Factor beta / biosynthesis*
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / urine


  • RNA, Messenger
  • Transforming Growth Factor beta
  • Sodium Chloride
  • Tetraethylammonium