Abstract | 2-[125I]Iodomelatonin was used to compare the binding and pharmacological characteristics of the melatonin receptor sites found in chicken brain and sheep pars tuberalis. Scatchard analysis and kinetic experiments showed that 2-[125I]iodomelatonin binds to a single class of site in both tissues with high affinity (Kd 20–34pM). Competition experiments, using 21 analogues of melatonin, gave inhibition constants (Ki) for the two sites which were significantly correlated (r = 0.985, n = 21, P < 0.0001). We conclude that the 2-[125I]iodomelatonin binding sites in sheep pars tuberalis and chicken brain have identical binding and pharmacological characteristics. |
---|