Study summary · research use only
A new series of highly potent growth hormone-releasing peptides derived from ipamorelin
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This study describes a new series of GH secretagogues derived from ipamorelin, using the peptidomimetic fragment 3-(aminomethyl)benzoic acid and sequential backbone N-methylations to reduce size and hydrogen-bonding sites. The abstract reports several compounds released GH with high potency in a rat pituitary cell assay and in anesthetized rats. The tetrapeptide NNC 26-0235 (3-(aminomethyl)benzoyl-D-2Nal-N-Me-D-Phe-Lys-NH2) showed, after iv administration, in vivo potency comparable to ipamorelin, GHRP-2, and GHRP-6, with an ED50 in swine of 2 nmol/kg and 10% oral bioavailability in dogs; NNC 26-0235 and ipamorelin increased basal GH more than 10-fold after oral doses of 1.8 and 2.7 mg/kg. The tripeptide NNC 26-0323 showed 20% oral bioavailability in rats but lacked in vivo potency.
Abstract
A new series of GH secretagogues derived from ipamorelin is described. In an attempt to obtain oral bioavailability, by reducing the size and the number of potential hydrogen-bonding sites of the compounds, a strategy using the peptidomimetic fragment 3-(aminomethyl)benzoic acid and sequential backbone N-methylations was applied. Several compounds from this series release GH with high in vitro potency and efficacy in a rat pituitary cell assay and high in vivo potency and efficacy in anesthetized rats. The tetrapeptide NNC 26-0235 (3-(aminomethyl)benzoyl-D-2Nal-N-Me-D-Phe-Lys-NH2) shows, following iv administration, comparable in vivo potency to ipamorelin, GHRP-2, and GHRP-6 with an ED50 in swine at 2 nmol/kg. NNC 26-0235 demonstrated a 10% oral bioavailability in dogs, and NNC 26-0235 and ipamorelin were able to increase basal GH level by more than 10-fold after oral administration of a dose of 1.8 and 2.7 mg/kg, respectively. The tripeptide NNC 26-0323 (3-(aminomethyl)benzoic acid-N-Me-D-2Nal-N-Me-D-Phe-ol) which showed moderate in vitro potency but lacked in vivo potency demonstrated a 20% oral bioavailability in rats.
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