In young goats, giving the peptide GHRP‑2 (KP102) by mouth raised growth hormone levels, especially at a dose of 10 mg per kilogram of body weight. Older goats also showed a rise, but it was smaller and similar for both 5 mg/kg and 10 mg/kg doses. The hormone IGF‑1 did not change during the short test period.

To assess the oral activity of KP102 (also known GHRP-2) on growth hormone (GH) release in ruminant animals, 5 or 10 mg/kg body weight (BW) of KP102 dissolved in saline was orally administered twice at 2 hr-intervals to either 1- or 3-mo-old goats (n = 5-6). Plasma GH concentrations in the 1-mo-old goats were elevated at 15 min after the first administration of both 5 and 10 mg/kg BW of KP102. Significant elevation of GH concentrations continued until 180 min after 10 mg/kg BW of KP102, whereas the elevated GH levels after the administrations of 5 mg/kg BW of KP102 subsided to basal concentrations within 90 min. The second administration of 10 mg/kg BW of KP102 failed to elevate the GH concentration, but 5 mg/kg BW of KP102 abruptly stimulated GH release. Plasma GH concentrations in the 3-mo-old goats were also significantly elevated after the administration of both 5 and 10 mg/kg BW of KP102. The plasma GH responses to 5 and 10 mg/kg BW of KP102 were almost identical. The elevated GH levels after the first administration of KP102 tended to be maintained throughout the experiment, and a transient increase in plasma GH levels was observed after the second administration. However, the stimulatory effect of KP102 on GH release in the 3-mo-old goats was small and less abrupt than that in the 1-mo-old goats. The concentrations of insulin-like growth factor-I were not increased by KP102 during the brief sampling periods used in this experiment. These results show that the oral administration of the peptidergic GH secretogogue KP102 stimulates GH release in a ruminant species, and that the oral activity of KP102 on GH release is modified by the age.