ABSTRACT
Among the GH-releasing class of compounds, a novel and potent growth hormone-releasing peptide (GHRP) analog, hexarelin* [His-n-Trp(2Me)Ala-Trpn-Phe-Lys-NH2] has recently been developed. The compound displays high stability owing to the substitution of the D-tryptophan(2ME) position, and is more potent than GHRP-6 in vitro (1). Preclinical studies of hexarelin in rats and dogs following intravenous (iv) and subcutaneous (sc) administration have demonstrated that the peptide elicits a long-lasting GH release and is more effective than GHRP-6 (2,3). In humans, intravenous (iv) administration of hexarelin results in substantial dose-dependent increases in plasma GH concentrations (4). Following intravenous, subcutaneous, intranasal, and oral administration of hexarelin to humans, Ghigo et al. have demonstrated that all routes of administration elicit significant GH response (5). *Hexarelin is a trademark for examorelin (l.N.N.).
