Suppression of S-methylglutathione-induced tentacle ball formation by peptides and nullification of the suppression by TGF-β in hydra

Abstract

Tentacle ball formation (TBF) in Hydra elicited by S-methylglutathione (GSM) was modulated by a number of biologically active peptides. Hydra fed on Artemia, which had been hatched in a common salt solution supplemented with LiCl and ZnCl2, easily induced TBF in response to GSM after pretreatment with trypsin. After Hydra were treated with 100 pg/ml trypsin for 10 min, the response to GSM (TBF) was sensitively suppressed by acidic fibroblast growth factor and other biologically active peptides for > 10 h. Various peptides, but not transforming growth factor beta (TGF-β), suppressed GSM-induced TBF in a specific pattern for each peptide. However, TGF-β was unique in that it did not suppress the response to GSM, but nullified the suppressive effect of other peptides. Only active TGF-β nullified the suppressive effect of the peptides, and the latent form of TGF-β neither suppressed GSM-induced TBF nor nullified the suppressive effect of other peptides. Members of the TGF-β family suppressed GSM-induced TBF. These results indicate that all peptides examined, except for TGF-β, suppressed the response to GSM in a manner specific to each peptide. This assay system would be useful in identification of biologically active peptides.