Table 1. Biodistribution of [Nle¹⁴,¹²⁵I-Tyr⁴⁰-NH₂]Ex-4 in mice bearing Ins-1E xenografts.

Organ	%IA/g #
	1 h a	1 h–blocked	4 h	24 h
Blood	2.9±0.2	2.9±0.5	2.2±0.2*	0.1±0.0**
Heart	1.3±0.2	0.7±0.1*	0.8±0.1*	0.1±0.0**
Lung	30.5±3.6	2.2±0.0**	8.8±1.8**	0.1±0.0**
Liver	1.5±0.1	1.1±0.3	0.8±0.0	0.1±0.0**
Spleen	1.5±0.3	1.1±0.2	1.1±0.1**	0.1±0.0**
Pancreas	25.3±4.2	1.9±0.1**	10.4±2.5**	0.9±0.5**
Stomach	13.4±1.2	9.3±0.6*	8.3±2.1*	0.3±0.0**
Intestine	3.9±0.5	1.3±0.2**	1.8±0.4**	0.1±0.0**
Kidney	7.5±0.7	5.7±0.1*	3.2±0.3**	0.2±0.0**
Adrenal	1.4±0.3	0.8±0.2	0.8±0.4	0.2±0.1**
Muscle	0.4±0.0	0.5±0.0	0.3±0.0*	0.1±0.0**
Bone	0.6±0.4	1.0±0.3	0.7±0.1	0.1±0.0
Ins-1E	72.8±12.2	5.9±0.6**	22.4±2.9**	3.7±2.5**
Tumor-to-blood	25.1		10.2	37
Tumor-to-muscle	182		74.7	37
Tumor-to-kidney	9.7		7.0	18.5
Tumor-to-pancreas	2.9		2.2	4.1

^# Values are mean±standard deviation (n = 3–4).

^a-The peptide mass is 0.5 pmol, based on the specific activity of ¹²⁵I.

*p<0.05.

**p<0.01, compared to 1h group.