Abstract:
:The purpose of this study was to characterize the biological activity of the synthetic rat growth hormone releasing factor analogue rGRF(1-29)NH2 and to compare its action on growth hormone (GH) release to that of authentic rGRF(1-43)OH. We first compared the concentration-response characteristics of the two peptides in static incubation, and then examined the reversibility and repeatability of the GH response in a perifusion system. Authentic rGRF(1-43)OH was significantly more potent in static incubation (EC50 = 3 x 10(-11) M) than the analogue (5 x 10(-11) M), whereas the reverse held true in perifusion. The shapes of the GH responses were similar for both peptides in the perifusion system. However, while the GH response to authentic rGRF was repeatable, the prior administration of rGRF(1-29)NH2 significantly reduced (greater than 50%) the GH response to the subsequent administration of either rGRF(1-29)NH2 or rGRF(1-43)OH. Thus authentic rGRF and the synthetic fragment may have different actions at the level of the GRF receptor or at a postreceptor (second messenger) step.
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Kraicer J,French MB,Lussier BT,Moor BC,Brazlan Pdoi
10.1139/y91-026subject
Has Abstractpub_date
1991-02-01 00:00:00pages
181-4issue
2eissn
0008-4212issn
1205-7541journal_volume
69pub_type
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