Table 3.

Effects of cytotoxic SST hybrid AN-238 and its carrier analog RC-121 on hGH-RH(1-29)NH₂ or forskolin-induced GH-release in dispersed rat pituitary superfusion system in vitro

Compound	Exposure time, min	GH response, ng		Inhibition (%)	GH response, ng		Inhibition (%)
		Control	RC-121		Control	AN-238
1 nM GH-RH + 1 nM analog	3	560	22	96	493	80	84
1 nM GH-RH + 1 nM analog	30	2,598	0	100	1,939	101	95
0.2 nM GH-RH + 0.1 nM analog	6	260	0	100	214	23	91
0.2 nM GH-RH + 0.5 nM analog	6	277	0	100	215	18	92
4 μM forskolin + 0.5 nM analog	6	760	90	88	760	230	70
10 μM forskolin + 2 nM analog	6	696	294	58	554	258	54

Cells were exposed to the secretagogues alone or in combination with the SST analogs for different duration and at various concentrations. The GH-release inhibitory activities of the analogs are expressed as relative GH-releasing potencies (ng, “net integral” values) of the secretagogues administered with or without the analogs.