title: Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog.
abstract: In vivo bioconjugation to the free thiol on Cys34 of serum albumin by a strategically placed reactive group on a bioactive peptide is a useful tool to extend plasma half-life. Three maleimido derivates of human GH-releasing factor (hGRF)(1-29) were synthesized and bioconjugated to human serum albumin ex vivo. All three human serum albumin conjugates showed enhanced in vitro stability against dipeptidylpeptidase-IV and were bioactive in a GH secretion assay in cultured rat anterior pituitary cells. When the maleimido derivatives were individually administered sc to normal male Sprague Dawley rats, an acute secretion of GH was measured in plasma. The best compound, CJC-1295, showed a 4-fold increase in GH area under the curve over a 2-h period compared with hGRF(1-29). CJC-1295, a tetrasubstituted form of hGRF(1-29) with an added N epsilon-3-maleimidopropionamide derivative of lysine at the C terminus, was selected for further pharmacokinetic evaluation, where it was found to be present in plasma beyond 72 h. A Western blot analysis of the plasma of a rat injected with CJC-1295 showed the presence of a CJC-1295 immunoreactive species on the band corresponding to serum albumin, appearing after 15 min and remaining in circulation beyond 24 h. These results led to the identification of CJC-1295 as a stable and active hGRF(1-29) analog with an extended plasma half-life.
authors.affiliation: Department of Research, ConjuChem Inc., 225 President-Kennedy Avenue, Montreal, Quebec, Canada H2X 3Y8.
authors.forename: Lucie
authors.initials: L
authors.lastname: Jetté
authors.forename: Roger
authors.initials: R
authors.lastname: Léger
authors.forename: Karen
authors.initials: K
authors.lastname: Thibaudeau
authors.forename: Corinne
authors.initials: C
authors.lastname: Benquet
authors.forename: Martin
authors.initials: M
authors.lastname: Robitaille
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pellerin
authors.forename: Véronique
authors.initials: V
authors.lastname: Paradis
authors.forename: Pieter
authors.initials: P
authors.lastname: van Wyk
authors.forename: Khan
authors.initials: K
authors.lastname: Pham
authors.forename: Dominique P
authors.initials: DP
authors.lastname: Bridon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D018819:Dipeptidyl Peptidase 4 / Q000494:pharmacology; D004355:Drug Stability; D013007:Growth Hormone-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D006207:Half-Life; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017337:Sermorelin / Q000493:pharmacokinetics; D012709:Serum Albumin / Q000378:metabolism / Q000494:pharmacology*; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism*
chemical_list: C502076:CJC 1295; D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D012709:Serum Albumin; D014157:Transcription Factors; D017337:Sermorelin; D013007:Growth Hormone-Releasing Hormone; C059148:somatotropin releasing hormone (1-29); D018819:Dipeptidyl Peptidase 4