title: Characterization of alpha 2-adrenergic receptors in the human colon adenocarcinoma cell line HT 29 in culture by [3H]yohimbine binding.
abstract: The presence of specific binding sites for [3H]yohimbine, a labelled alpha 2-adrenergic agent, on crude membranes of HT 29 cells established in culture from a human colon adenocarcinoma, is reported. The estimated affinity and number of sites (KD = 6.3 +/- 0.9 nM; Bmax = 224 +/- 28 fmol/mg protein) as well as the relative potencies of adrenergic agonists (clonidine greater than phenylephrine greater than amidephrine) and adrenergic antagonists (yohimbine greater than dihydroergotamine much greater than prazosin) to displace [3H]yohimbine binding indicate that the yohimbine sites of these cancer cells have similar characteristics to the alpha 2-adrenergic receptors described in other tissues.
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009363:Neoplasm Proteins / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000145:classification / Q000378:metabolism*; D015016:Yohimbine / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine