A method for evaluation of activity of growth hormone-releasing hormone analogues.
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.
Izdebski
Jan
J
Peptide Laboratory, Department of Chemistry, Warsaw University, Warsaw, Poland. zncmkp@op.pl
Kunce
Danuta
D
Witkowska
Ewa
E
Wolińska-Witort
Ewa
E
Chmielowska
Magdalena
M
Baranowska
Bogusława
B
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
D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone