TABLE 2

Biologic properties of ghrelin analogs—competitive binding studies, receptor activation assay, and orexigenic effect

Data from in vitro studies are presented as the means ± S.E.M. of at least three separate experiments. In the competitive binding studies, K_i was calculated using the Cheng-Prusoff equation. EC₅₀ is the concentration of peptide that yielded 50% of the maximal effect. Food intake was analyzed at 495 minutes after the s.c. administration of tested peptides and is presented as percentage of the saline-treated group consumption to compare data from multiple experiments. Data were evaluated by unpaired t test (n = 5–8 mice in at least two experiments).

Analog	¹²⁵I-Ghrelin Binding to Human GHS-R1a (LLC-PK1 Membranes)	Activation of Bla Reporter Gene (GHS-R1a–Overexpressing Cells)	Food Intake in Fasted Mice (5 mg/kg s.c.) at 495 min
	K_i	EC₅₀	Percentage of Saline-Treated Group	Significance vs.:
	K_i	EC₅₀	Percentage of Saline-Treated Group	Saline	Ghrelin
	nM	nM
Ghrelin	0.69 ± 0.05	0.59 ± 0.33	167.9 ± 19.4	**	—
[Dpr³]ghr	0.64 ± 0,03	NT	223.4 ± 32.5	**	NS
1	0.63 ± 0.03	0.91 ± 0.13	416.6 ± 73.2	***	**
2	2.11 ± 0.16	2.14 ± 1.05	418.8 ± 45.4	***	***
3	0.65 ± 0.07	2.39 ± 0.23	425.2 ± 73.0	***	**
4	2.02 ± 1.11	4.19 ± 1.54	425.5 ± 49.5	***	***
5	4.25 ± 0.64	4.42 ± 0.58	303.8 ± 40.5	***	**
6	1.04 ± 0.06	0.49 ± 0.08	421.1 ± 75.2	***	**
7	6.42 ± 0.51	1.01 ± 0.19	437.8 ± 66.8	***	**
8	5.90 ± 0.38	0.99 ± 0.13	270.5 ± 38.3	***	^*
9	2.45 ± 0.37	1.29 ± 0.71	667.6 ± 126	***	***
10	16.8 ± 1.81	9.50 ± 9.30	836.8 ± 176	***	***
11	230 ± 25.6	170 ± 103	184.7 ± 82.7	NS	NS
12	126 ± 7.18	45.8 ± 23.9	201.4 ± 64.0	NS	NS
13	4.72 ± 0.45	NT	144.8 ± 17.1	NS	NS
14	6.10 ± 0.39	NT	172.7 ± 21.4	^*	NS
15	23.4 ± 5.34	NT	148.8 ± 12.1	^*	NS
16	20.8 ± 4.32	NT	174.2 ± 17.2	**	NS
17	4.27 ± 0.45	2.94 ± 0.44	373.9 ± 209	NS	NS
18	14.9 ± 2.94	4.38 ± 1.90	394.4 ± 81.8	**	***
19	3.71 ± 0.78	NT	280.9 ± 48.9	**	^*
20	3.38 ± 0.90	NT	353.6 ± 66.4	***	^*
21	5.99 ± 0.79	1.51 ± 0.30	297.1 ± 51.9	^*	**
22	50.9 ± 8.65	3.79 ± 2.67	333.4 ± 59.4	**	**
23	1.52 ± 0.43	NT	128.6 ± 39.8	NS	NS
24	0.83 ± 0.02	NT	192.0 ± 20.2	**	NS
25	0.27 ± 0.12	NT	181.3 ± 21.9	**	NS
26	0.79 ± 0.08	NT	195.6 ± 28.9	**	NS

bla, β-lactamase; ghr, ghrelin; NS, not significant; NT, not tested.
↵* P < 0.05; **P < 0.01; ***P < 0.001.