Extracts of intestinal epithelia from the European eel (Anguilla anguilla)
stimulated cGMP production in the T84 human colon carcinoma cell line which
suggested the presence of a guanylin-like peptide in this teleost fish. De
generate oligonucleotide primers were subsequently used in RT-PCR resulting
in the amplification, cloning, and sequencing of two cDNAs which represent
possible 5' spliceoforms of an eel homologue of the mammalian peptide, gua
nylin. Northern blotting indicated that the main site of expression of the
eel peptide is in the intestine with much lower signals also detected in th
e kidney. Intestinal expression of guanylin mRNA is up-regulated in both no
nmigratory "yellow" and the more sexually mature, migratory "silver" eels f
ollowing acclimation to the seawater environment. These results suggest tha
t this peptide signalling system may play a role in osmoregulation in euryh
aline teleost fish during migration between the marine and freshwater envir
onments. (C) 2001 Academic Press.