GHRP-2

Ten publications are cited, from 1997 to 2023. Four are clinical intervention studies published between 1997 and 2002: two in adults with prolonged critical illness, one in men and women examining the peptide's interaction with L-arginine at rest and during exercise, and one in children with short stature. Three clinical papers from 2018 to 2023 used GHRP-2 as a stimulation test in patients with pituitary tumours. The remaining three are laboratory studies from 2015 and 2016, on human ovarian granulosa cells, a urine assay for growth hormone-releasing peptides and their metabolites, and a PEGylated form of the peptide.

In prolonged critical illness, a 1999 study described night-time growth hormone, thyrotrophin and prolactin release falling out of synchrony, and reported that GHRP-2 infusion synchronised them. A 2002 study in critically ill men gave GHRP-2 with TRH and GnRH and reported reactivation of the growth hormone, thyrotrophin and luteinising hormone axes, with metabolic changes that were absent on GHRP-2 alone. The exercise study reported a greater-than-additive response to L-arginine and GHRP-2 at rest, which exercise reduced in relative size while enlarging each agent's separate effect. In children with short stature, GHRP-2 was reported as well tolerated, with a modest but significant rise in growth velocity. In the diagnostic papers, peak growth hormone during the test tracked how severe the hypopituitarism was and how far growth hormone secretion recovered after surgery, and correlated with adrenal function in older patients. In the laboratory, GHRP-2 reduced COX-2 and IL-8 expression induced by protein kinase C activation in granulosa cells, and PEGylation gave more stable activity, consistent with a longer plasma half-life.

All four intervention studies are more than two decades old and come from narrow groups: critically ill adults, one physiology study and one paediatric study. The diagnostic papers use GHRP-2 as a probe of pituitary reserve, so they describe the patients' pituitary function rather than the effects of repeated exposure. The laboratory work covers a single cell type, an analytical method and a formulation change.