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Desensitization of the D-2 dopamine receptor and the β2-adrenoceptor in the intermediate lobe of the rat pituitary gland

1983; Elsevier BV; Volume: 5; Issue: 6 Linguagem: Inglês

10.1016/0197-0186(83)90107-9

1872-9754

Kazuhiro Miyazaki, Juan M. Saavedra, C. E. Thomas, John W. Kebabian,

Stress Responses and Cortisol

A D-2 dopamine receptor and a β2-adrenoceptor occur in the intermediate lobe of the rat pituitary gland (IL). Exposure of intact IL tissue to a D-2 agonist diminished the ability of dopaminergic agonists [but not 5′-guanylyl imidodiphosphate (Gpp(NH)p)] to inhibit adenylate cyclase activity. Conversely, exposure of intact IL tissue to a β-adrenergic agonist diminished the ability of a β-adrenergic agonist (but not forskolin) to stimulate adenylate cyclase activity. Treatment of ovariectomized rats with 17β-estradiol desensitizes the β2-adrenoceptor but not the D-2 receptor. Desensitization of the IL catecholamine receptors is discussed within the framework of a previously published “working model” of these receptors.