[Analysis of the glucocorticoid receptor of bovine tracheal smooth muscle].
Though the therapeutic efficacy of glucocorticoids on bronchial asthma has been attributed mainly to their anti-allergic and anti-inflammatory effects, the possibility of intervention of glucocorticoids in bronchial asthma might be an important parallel process. However, little is known about the mechanism of glucocorticoid action on tracheal muscle and there is insufficient basic information about the glucocorticoid receptor of tracheal muscle. Accordingly we set out to analyze the glucocorticoid receptor of bovine tracheal muscle. Bovine tracheal muscle was used because it is plentiful enough for biochemical analysis. Our results showed that a small amount (0.08 pmol/mg.protein) of glucocorticoid binder of high affinity (kd = 4.6 nM) was present in the cytosol of bovine bronchial muscle. The binder did not show any affinity for estradiol, dihydrotestosterone or andronsterone, but showed a low affinity for progesterone. Furthermore, the binder underwent salt-dependent variation of its molecular form (9.2S under low salt condition and 4.6S under high salt condition) typical of steroid receptors. These results indicated the presence of a glucocorticoid receptor in the tracheal muscle, suggesting that glucocorticoid acts on bronchial muscle in therapeutic practice on bronchial asthma.
Otsuka
T
T
Fukuda
T
T
Makino
S
S
Murayama
A
A
D000818:Animals; D002417:Cattle; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000032:analysis*; D011965:Receptors, Glucocorticoid / Q000032:analysis*; D014132:Trachea
D011965:Receptors, Glucocorticoid