Pharmacological characteristics of KP-102 (GHRP-2), a potent growth hormone-releasing peptide

Arzneimittelforschung. 2004;54(12):857-67. doi: 10.1055/s-0031-1297041.


KP-102 (D-alanyl-3-(2-naphthyl)-D-alanyl-L-alanyl-L-tryptophyl-D-phenylalanyl-L-lysinamide dihydrochloride, growth hormone-releasing peptide-2, GHRP-2, pralmorelin, CAS 158861-67-7), is a potent synthetic growth hormone (GH) secretagogue. In the present study, the pharmacological characteristics of the GH-releasing property of KP-102 were investigated by means of in vivo and in vitro experiments. In conscious rats, the GH-releasing activity of KP-102 was more potent than that of exogenously injected GH-releasing hormone (GHRH). Under pentobarbital anesthesia in which endogenous somatostatin secretion is known to be decreased, KP-102 and GHRH, both showed an almost equivalent GH-releasing potency, which was also similar to that of KP-102 in conscious rats. Besides, KP-102 showed GH-releasing activity in conscious dogs as well, while GHRH failed to increase serum GH levels in conscious dogs. These findings suggest that the GH-releasing activity of KP-102 was less sensitive to GH suppression by endogenous somatostatin as compared with that of GHRH. The GH-releasing activity of KP-102 was completely absent in hypophysectomized rats, but present in median eminence-lesioned rats in which secreted GH amounts were significantly less than those normal rats, indicating necessity of the median eminence (endogenous GHRH) to exert the full activity of KP-102 in GH stimulation. KP-102 directly stimulated GH secretion from cultured rat anterior pituitary cells, although the GH-releasing potency of KP-102 was significantly weaker than that of GHRH in vitro. In conscious rats, KP-102 stimulated the secretion of both adrenocorticotrophic hormone (ACTH) and corticosterone, but not of prolactin. Three weeks administration of KP-102 showed growth-accelerating effect, a slight increase of body weight and wet weight of some organs in both normal and monosodium glutamate (MSG)-treated rats. These results suggest that KP-102 showed specific GH-releasing activity apart from slight ACTH secretion, and that the GH-releasing activity was stable in comparison with that of exogenously injected GHRH.

MeSH terms

  • Adrenocorticotropic Hormone / blood
  • Anesthesia
  • Animals
  • Area Under Curve
  • Cells, Cultured
  • Corticosterone / blood
  • Dogs
  • Growth Hormone / metabolism
  • Growth Hormone-Releasing Hormone / pharmacology*
  • Hormones / metabolism
  • Hypnotics and Sedatives
  • Hypophysectomy
  • Hypothalamus / drug effects
  • Hypothalamus / metabolism
  • Male
  • Median Eminence / physiology
  • Oligopeptides / pharmacology*
  • Pentobarbital
  • Pituitary Gland / drug effects
  • Pituitary Gland / metabolism
  • Prolactin / blood
  • Rats
  • Rats, Sprague-Dawley
  • Sodium Glutamate / pharmacology


  • Hormones
  • Hypnotics and Sedatives
  • Oligopeptides
  • Adrenocorticotropic Hormone
  • Prolactin
  • Growth Hormone
  • Growth Hormone-Releasing Hormone
  • growth hormone-releasing peptide-2
  • Pentobarbital
  • Sodium Glutamate
  • Corticosterone