Saturation binding of [3H]oestradiol has been determined using exchange conditions, on nuclei from DMBA tumours from rats treated prior to sacrifice with oestradiol and tamoxifen alone or in combination. Application of a model to the binding data. enabled the amounts (C2) and apparent dissociation constants (Kdapp) of a second lower affinity binding component to be determined as well as the amount of a higher affinity site (C1) and its dissociation constant (K1). Kdappdid not change significantly with any pretreatment but 2 h after oestradiol (5μg) and after tamoxifen alone there was a significant decrease in Kdcompared with control. It is suggested that the difference in Kdof the higher affinity binding sites in control and 2 h oestradiol treated animals may be due to the loss of an essential co-factor, possibly cytosolic, when nuclei are isolated in the absence of ligand. © 1988.
Clark, E. R., Mackay, D., & Robinson, S. P. (1988). Application of a mathematical model for two component receptor binding to two high affinity oestrogen binding sites in nuclei from dmba rat mammary tumours. Journal of Steroid Biochemistry, 29(4), 375–380. https://doi.org/10.1016/0022-4731(88)90245-2