Submandibular gland peptides and the modulation of anaphylactic and endotoxic reactions
Ronald Mathison ( Canada )
Sitbmandibular glandpeptide-T (SGP-T), a hepta- peptide with the sequence ofthreonine, aspartate, isoleucine, phenylalanine, glutamate, glycine, gfycine (TDIFEGG), was isolated from the Sitbmandibular glands of rats based on the ability of extracts of these glands to reduce the hypotension induced by bacterial lipopolysaccharide. SGP-T was also found to decrease the severity of the cardiovascular shock provoked by antigen administration to ovalbumin-sensitized rats. An analysis of the structure-activity relationship re vealed that three amino acids, phenylalanine, gluta mate,glycine (PEG), located in the carboxy terminal of SGP-T were sufficient to inhibit intestinal anaphylaxis in vitro. Inter estingly, the D-isomeric form of PEG (feG) did not inhibit anaphylaxis in the in vitro assay. However, both tripeptides, FEG and feG, significantly reduced anaphylactic hypotension and intestinal anaphylaxis in vivo. SGP-T may be a prototype of a family of small peplides that modulate the immune and smooth muscle reactions to severe inflammatory stress. SGP- T preferentially inhibits cardiovascular anaphylaxis, whereas feG exhibits a high degree of selectivity for inhibiting intesti
nal anaphylaxis in vivo.
Biomed Rev 1998; 9: 101-106
Received for publication 15 May 1998 and accepted 11 September1998.
Corespondence and reprint requests to Dr Ronald Mathison. Department of Physiology and Biophysics. The University of Calgary. 3330 Hospital Drive NW. Calgary, Alberta. Canada T2N 4N1. Tel: 1 (403) 220 6031. Fax: 1 (403)2834740.