Characterization of specific binding sites for corticosterone in mouse liver plasma membrane.
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.
Trueba
M
M
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad del País Vasco/Euskal Herriko Unibertsitatea, Bilbao, Spain.
Ibarrola
I
I
Vallejo
A I
AI
Sancho
M J
MJ
Marino
A
A
Macarulla
J M
JM
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism*; D003345:Corticosterone / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D011987:Receptors, Steroid
D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; C024357:corticosterone receptor; D011433:Propranolol; D003345:Corticosterone; D010646:Phentolamine