Trueba M, Ibarrola I, Vallejo A I, Sancho M J, Marino A, Macarulla J M
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco/Euskal Herriko Unibertsitatea, Bilbao, Spain.
Membr Biochem. 1989;8(4):229-39. doi: 10.3109/09687688909026817.
The specific binding of [3H]corticosterone to mouse liver purified plasma membrane fractions is a saturable, reversible, and temperature-dependent process. Only one type of independent and equivalent binding sites has been determined in plasma membrane (Kd = 4.1 nM and Bmax = 3368 fmol/mg). As can be deduced from displacement data obtained in plasma membrane, the high-affinity binding site is different from nuclear glucocorticoid, nuclear progesterone, and Na+, K(+)-ATPase digitalis receptors. Probably this corticosterone binding site or receptor is the same one determined previously for [3H]cortisol in mouse liver plasma membrane. Such beta- and alpha-adrenergic antagonists as propranolol and phentolamine did not affect [3H]corticosterone binding to plasma membranes; therefore, this binding site is independent of these receptors. The binding sites in plasma membranes are not exclusive for corticosterone, but other steroids are also bound with very different affinities.
