2-(125I) iodomelatonin binding sites in rat adrenals: pharmacological characteristics and subcellular distribution.
Specific binding sites for 2-[125I] iodomelatonin, a selective radiolabeled melatonin receptor ligand, were detected and characterized in rat adrenal membranes. Saturation studies demonstrated that 2-[125I]iodomelatonin binds to a single class of sites with an affinity constant (Kd) of 541 pM and a total binding capacity (Bmax) of 3.23 fmol/mg protein. Competition experiments revealed that the relative order of potency of compounds tested was as follows: 6-chloromelatonin greater than 2-iodomelatonin greater than melatonin greater than 5-methoxytryptamine greater than 5-methoxytryptophol. The highest density of binding sites was found in membranes from nuclear (0.76 fmol/mg protein) and mitochondrial (1.82 fmol/mg protein) subcellular fractions.
Persengiev
S P
SP
Department of Immunoneuroendocrinology, Bulgarian Academy of Sciences, Sofia.
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D007457:Iodine Radioisotopes; D044094:Receptors, Melatonin; D017981:Receptors, Neurotransmitter; D008550:Melatonin