Abstract

In various animal models of tissue injury, corticotropin-releasing factor (CRF) and related peptides inhibit swelling, edema and loss of protein from the vascular compartment. To search for smaller peptide segments of CRF that might retain anti-inflammatory activity, the authors tested peptides similar to the carboxy terminals of ovine (o) and human/rat (h/r) CRF. Also, because h/rCRF(35-39), -Arg-Lys-Leu-Met-Glu-, resembles Arg-Lys-Leu-Leu-Glu-, a sequence found in many intermediate filament proteins, analogous peptides were evaluated. Ovine CRF(21-41), -Met-Thr-Lys-Ala-Asp-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn-Arg-Lys- Leu-Asp-Ile-Ala-NH2, its carboxy terminal carboxyl derivative, oCRF(21-41)-OH, and the fragments, oCRF(26-41) and oCRF(30-41), were inactive when assayed at 5 mg/kg i.v. on edema induced in the pentobarbital-anesthetized rat's hindpaw after immersion in 58 degrees C water for 1 min. Crude peptides, D-Leu-Ala-Thr-D-Tyr-Arg-Lys-Leu-Leu-Glu-Ile-D-Leu-NH2 and D-Ala-His-Ser-D-Asn-Arg-Lys-Leu-Leu-Glu-Ile-D-Leu-NH2, were found to have activity in this bioassay. Characterization of the structures within the crude mixture revealed that substitution of the glutamic acid residue with an anisolyated glutamic acid (2-amino-5-(methoxyphenyl)-5-oxopentanoic acid) derivative, designated as (A*), increased the overall potency. The glutamyl-anisole derivative was a by-product of the temperature-dependent Friedel-Crafts acylation reaction that occurs during hydrogen fluoride cleavage of glutamyl-containing peptides.(ABSTRACT TRUNCATED AT 250 WORDS)