title: The uptake and release of ponasterone A by the Kc cell line of Drosophila melanogaster.
abstract: The association of ponasterone A (PNA) and 20-hydroxyecdysone with Kc cells is commensurate with their biological activity on this Kc cell line, the physiological activity ratio for PNA, 20-hydroxyecdysone and ecdysone is 1 : 50 : 2000, resp. Both association and release of [3H]-PNA are temperature-dependent, the activation energy was calculated as 16.7 cal (Arrhenius analysis). This association is compatible with unlabelled PNA and various ecdysteroids. The KD for PNA (Scatchard analysis) was estimated as 3.6 x 10(-9) M, giving the number of binding sites as approx. 1800 per cell.
mesh_terms: D002455:Cell Division; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004331:Drosophila melanogaster / Q000378:metabolism*; D004440:Ecdysone / Q000378:metabolism; D004441:Ecdysterone / Q000031:analogs & derivatives* / Q000378:metabolism*; D007700:Kinetics; D011956:Receptors, Cell Surface / Q000378:metabolism; D013696:Temperature
chemical_list: D011956:Receptors, Cell Surface; D004440:Ecdysone; D004441:Ecdysterone; C008999:ponasterone A