title: A method for evaluation of activity of growth hormone-releasing hormone analogues.
abstract: OBJECTIVE
  It has been found that hGH-RH analogues with increased resistance to enzymatic degradation have a much higher potency than the native hGH-RH (1-29)-NH2 and have an ability to partially reverse growth hormone deficiencies.
  
  
  OBJECTIVE
  The aim of these studies was to elaborate a method which can be used for preliminary evaluation of new GH-RH analogues both from the point of view of their potency to release GH and enzymatic stability.
  
  
  METHODS
  Two highly active GH-RH analogues with increased resistance to trypsin-like enzymes, and hGH-RH(1-29)-NH2 used as a standard, in doses 1 nM, 10 nM, and 100 nM were added to pituitary rat cell culture, and medium was collected after 30, 60, 120 and 240 min. GH concentration was measured by RIA kit.
  
  
  RESULTS
  It was observed that the potency of these two GH-RH analogues was several times higher than that of native compound. Moreover, the stimulation was much longer. This suggests that high activity of these analogues in vivo could be the result of increased enzymatic stability.
  
  
  CONCLUSIONS
  This method can be used for selecting more potent and more stable releasing peptides before in vivo evaluation.
authors: Peptide Laboratory, Department of Chemistry, Warsaw University, Warsaw, Poland. zncmkp@op.pl
authors: Jan
authors: J
authors: Izdebski
authors: Danuta
authors: D
authors: Kunce
authors: Ewa
authors: E
authors: Witkowska
authors: Ewa
authors: E
authors: Wolińska-Witort
authors: Magdalena
authors: M
authors: Chmielowska
authors: Bogusława
authors: B
authors: Baranowska
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004795:Enzyme Stability / Q000502:physiology; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008297:Male; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY
chemical_list: D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone