Torsello A, Luoni M, Schweiger F, Grilli R, Guidi M, Bresciani E, Deghenghi R, Müller E E, Locatelli V
Department of Pharmacology, University of Milan, Italy.
Eur J Pharmacol. 1998 Nov 6;360(2-3):123-9. doi: 10.1016/s0014-2999(98)00677-3.
Growth hormone-releasing peptides (GHRPs) are a class of small peptides that stimulate growth hormone (GH) release in several animal species, including the human. Moreover, GHRPs injected into the brain ventricles stimulate feeding in the rat. The aim of this study was to evaluate the GH-releasing properties of a series of novel GHRP analogs and the possible existence of functional correlations between the GH-releasing activity and the effects on feeding behavior. Two well-known hexapeptides, GHRP-6 and hexarelin, given s.c., dose dependently stimulated both GH release and feeding behavior in satiated rats. However, in a series of tri-, penta- and hexapeptide analogs of hexarelin, some compounds were active either on GH release or on eating behavior. Interestingly, even minor structural modifications resulted in major changes of the pharmacological profile. We conclude that GHRPs have orexigenic properties after systemic administration which are largely independent from the effects they exert on GH release.
生长激素释放肽（GHRPs）是一类小肽，可刺激包括人类在内的多种动物物种释放生长激素（GH）。此外，注入脑室的GHRPs会刺激大鼠进食。本研究的目的是评估一系列新型GHRP类似物的生长激素释放特性，以及生长激素释放活性与对摄食行为影响之间可能存在的功能相关性。两种著名的六肽，GHRP-6和六元瑞林，皮下给药后能剂量依赖性地刺激饱足大鼠的生长激素释放和摄食行为。然而，在六元瑞林的一系列三肽、五肽和六肽类似物中，一些化合物对生长激素释放或进食行为有活性。有趣的是，即使是微小的结构修饰也会导致药理学特征的重大变化。我们得出结论，全身给药后GHRPs具有促食欲特性，这在很大程度上独立于它们对生长激素释放的作用。
