title: Effect of glucocorticoids on alpha-2 adrenoceptors in vas deferens of reserpinized rat in organ culture.
abstract: The changes in alpha adrenoceptors in vasa deferentia of reserpinized rats in organ culture were examined by binding studies with 3H-clonidine, 3H-yohimbine and 3H-prazosin. On organ culture for 1 day, the 3H-clonidine binding sites decreased by 1.07 pmol/g tissue and after 2 days no binding sites were detectable. 3H-Yohimbine binding sites also decreased during culture, but in smaller extent than 3H-clonidine binding sites. On the other hand, 3H-prazosin binding sites showed no apparent change in amount during culture. Addition of 0.1 mM hydrocortisone or dexamethasone to the culture medium inhibited the decrease in 3H-clonidine binding sites (1.7 pmol/g tissue), and the effect of glucocorticoid was blocked by the inhibitors of protein synthesis, cycloheximide and puromycin. However, hydrocortisone showed no effect on the 3H-yohimbine and the 3H-prazosin binding sites. An anti-endocytotic agent, an anti-microtubular agent and protease inhibitors had no effects on the decrease of 3H-clonidine binding sites during culture. These results suggest that the amount of alpha-2 adrenoceptors can change rapidly while alpha-1 adrenoceptors are stable and that glucocorticoids are important in regulation of conformation of alpha-2 adrenoceptor through synthesis of certain protein(s).
mesh_terms: D000818:Animals; D003000:Clonidine / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009924:Organ Culture Techniques; D011224:Prazosin / Q000378:metabolism; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D012110:Reserpine / Q000494:pharmacology*; D014649:Vas Deferens / Q000378:metabolism*; D015016:Yohimbine / Q000378:metabolism
chemical_list: D005938:Glucocorticoids; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D003907:Dexamethasone; D012110:Reserpine; D003000:Clonidine; D006854:Hydrocortisone; D011224:Prazosin