The hypothalamic actions of KP102 (also called GHRP-2) on the release
of GH were studied in female goats. KP102 (10(-5) M) was perfused into
the goat hypothalamus through a microdialysis probe (CMA/10 probe wit
h a 4 mm membrane length) at a rate of 4 mu l/min for 90 min, and plas
ma GH concentrations before and after perfusion were measured. The int
rahypothalamic perfusion of 10(-5) M KP102 significantly stimulated GH
release in goats (P<0.05). The GH levels began to rise after commence
ment of perfusion, and reached a maximum mean value at 180 min. The co
ncentrations of GH at 165, 180, 195, 210, 225 and 240 min after commen
cement of perfusion of KP102 were significantly higher than the corres
ponding values for control animals (P<0.05). KP102 had no effect on GH
pulse frequency, but it significantly increased the GH pulse amplitud
e after the perfusion(P<0.05). In contrast to KP102, intrahypothalamic
perfusion of 10(-5) M GHRH had no effect on the stimulation of GH rel
ease in goats even if intravenous injection of 10(-5) M GHRH significa
ntly stimulated GH release (P<0.05). These results suggest that KP102
may act partly on the hypothalamus to stimulate GH release in goats.