Skip to main content

Table 1 Inhibitory concentrations 50% (IC50) ± SE of receptorphin competition on different opioid sites, assayed by displacement binding of a variety of opioid ligands.

From: Receptorphin: A conserved peptide derived from the sequence of the opioid receptor, with opioid displacement activity and potent antiproliferative actions in tumor cells

Opioid Source

DPDPE or DSLET

DAGO

EKC

Diprenorphin

EKC +DADLE

Diprenorphin +DADLE

MCF7

3.25 ± 0.42 × 10-9

1.43 ± 0.20 × 10-10

6.65 ± 1.01 × 10-11

5.78 ± 0.64 × 10-13

1.59 ± 0.14 × 10-10

>10-12

T47D

ND

ND

5.14 ± 0.74 × 10-10

>10-12

5.41 ± 0.57 × 10-11

>10-12

DU145

ND

6.52 ± 0.58 × 10-11

2.34 ± 0.55 × 10-11

ND

2.87 ± 0.22 × 10-11

ND

PC3

ND

4.30 ± 0.97 × 10-11

>10-6

ND

>10-6

ND

Rat

8.25 ± 0.81 × 10-8

1.81 ± 0.23 × 10-7

*1.85 ± 0.11 × 10-10

**5.77 ± 0.87 × 10-10

-

1.85 ± 0.43 × 10-10

Brain

   

2.65 ± 0.13 × 10-9

  
  1. *[3H]U60-593 was used as a selective kappa1 opioid ligand **Displacement curves were best fitted with a two-site model. See text for details. IC50s (in Moles/L) were calculated by sigmoidal fitting of displacement experiments. ND = not detected. Mean ± SE of three different experiments performed in duplicate.