GH releasing peptides--structure and kinetics.
A new class of small synthetic peptides has been developed which specifically release GH. They consist of 6-7 amino acids and release GH in animals as well as humans. So far 3 of these peptides have been administered to humans, i.e., GHRP-6, GHRP-1 and GHRP-2. As in rats, these 3 peptides have been found to be increasingly more effective in releasing GH in humans. All 3 GHRPs release GH more efficaciously than GHRH 1-44 NH2 in humans. Particularly note-worthy is that GHRP-6, GHRP-1 AND GHRP-2 all release GH after oral administration. Near maximal amounts of GH can be released after GHRP-1 and GHRP-2 oral administration. In the present studies, the GH responses and serum irGHRP levels after i.v., s.c. and oral administration have been determined in normal younger men and/or women. By each route of administration GH was very effectively released. Additionally, GH release was induced by oral GHRP-6 in children with various degrees of GH deficiency. Noteworthy is the synergistic release of GH induced by the combined i.v. bolus administration of 1 microgram/kg of GHRP-1 + GHRH 1-44NH2. Thus, these results demonstrate GHRPs' potential importance at the theoretical as well as pharmaceutical level.
Bowers
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Tulane University Medical Center, New Orleans, LA 70112.
D000284:Administration, Oral; D000328:Adult; D000595:Amino Acid Sequence; D002648:Child; D004357:Drug Synergism; D005260:Female; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000008:administration & dosage / Q000737:chemistry* / Q000493:pharmacokinetics*; D011863:Radioimmunoassay; D013997:Time Factors
D009842:Oligopeptides; C079956:alanyl-histidyl-(2-naphthyl)alanyl-tryptophyl-phenylalanyl-lysinamide; C041048:growth hormone releasing hexapeptide; D013006:Growth Hormone