Renal effects of serine-7 analog of lymphoguanylin in ex vivo rat kidney

Manasses C. Fonteles, Stephen L. Carrithers, Helena S.A. Monteiro, Andre F. Carvalho, Gustavo R. Coelho, Richard N. Greenberg, Leonard R. Forte

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Guanylin and uroguanylin compose a family of natriuretic, diuretic, and kaliuretic peptides that bind to and activate apical membrane receptor guanylyl cyclase signaling molecules in renal and intestinal epithelia. Recently, a complementary DNA encoding an additional member of the guanylin family of cGMP-regulating peptides was isolated from lymphoid tissues of the opossum and was termed lymphoguanylin (LGN). A peptide analog of opossum LGN was synthesized containing a single disulfide bond with the internal cysteine-7 replaced by a serine residue (LGNCys7→Ser7). The biological activity of LGNSer was tested by using a cGMP bioassay with cultured T84 (human intestinal) cells and opossum kidney (OK) cells. LGNSer has potencies and efficacies for activation of cGMP production in the intestinal and kidney cell lines that are 100- and 1,000-fold higher than LGN, respectively. In the isolated perfused rat kidney, LGNSer stimulated a maximal increase in fractional Na+ excretion from 24.8 ± 3.0 to 36.3 ± 3.3% 60 min after administration and enhanced urine flow from 0.15 ± 0.01 to 0.24 ± 0.01 ml.g-1.min-1.LGNSer (0.69 μM) also increased fractional K+ excretion from 27.3 ± 2.3 to 38.0 ± 3.0% and fractional Cl- excretion from 26.1 ± 0.8 to 43.5 ± 1.9. A ninefold increase in the urinary excretion of cGMP from 1.00 ± 0.04 to 9.28 ± 1.14 pmol/ml was elicited by LGNSer, whereas cAMP levels were not changed on peptide administration. These findings demonstrate that LGNSer, which contains a single disulfide bond like native LGN, activates guanylyl cyclase-C (GC-C) receptors in T84 and OK cells and may be very helpful in studying the physiological importance of activation of GC-C in vivo. LGNSer also exhibits full activity in the isolated perfused kidney equivalent to that observed previously with opossum uroguanylin, suggesting a physiological role for LGN in renal function. Thus the single amino acid substitution enhances the activity and potency of LGN.

Original languageEnglish
Pages (from-to)F207-F213
JournalAmerican Journal of Physiology - Renal Physiology
Issue number2 49-2
StatePublished - Feb 2001


  • Cyclic guanosine 5′-monophosphate
  • Escherichia coli heat-stable enterotoxin
  • Guanylin
  • Guanylyl cyclase-C
  • Kidney
  • Uroguanylin

ASJC Scopus subject areas

  • Physiology
  • Urology


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