Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

AtT-20 cells comprise a mouse anterior pituitary tumor cell line that synthesizes and secretes adrenocorticotropin hormone (ACTH). beta-Adrenergic receptors were characterized on AtT-20 cells using receptor binding methodology and the ability of beta-receptor agonists to stimulate intracellular cyclic adenosine 3':5'-monophosphate (cAMP) formation and the release of ACTH immunoreactivity. The density of beta-receptors on membrane preparations of these cells is 64 fmol/mg of protein and their affinity constant (KD value) for tritiated dihydroalprenolol is 11 nM. The binding of [3H] dihydroalprenolol to AtT-20 cells is stereoselectively inhibited by propranolol and isoproterenol but is not affected by phentolamine. The beta-receptors on these cells appear to be of the beta 2-receptor subtype since a selective beta 2-receptor agonist, salmefamol, can inhibit [3H]dihydroalprenolol binding, whereas practolol, a beta 1-receptor blocker, is ineffective. (-)-Isoproterenol stimulates cAMP formation in AtT-20 cells and this effect is blocked by dl-propranolol. Both l-epinephrine and l-norepinephrine induce dose-dependent increases in cAMP formation with the former agonist being more potent. Salmefamol also stimulates cAMP formation in these cells. The secretion of ACTH from AtT-20 cells is induced by (-)-isoproterenol as well as by other adrenergic agonists. The isoproterenol effect on ACTH release is stereoselective, calcium dependent, and blocked by dl-propranolol but not by phentolamine or practolol.
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PMID:Activation of beta 2-adrenergic receptors on mouse anterior pituitary tumor cells increases cyclic adenosine 3':5'-monophosphate synthesis and adrenocorticotropin release. 630 Mar 55

Previous work in our laboratory has shown that stimulation of beta 2-adrenergic receptors on mouse anterior pituitary tumor cells causes the secretion of immunoreactive adrenocorticotropin (ACTH). The present study was designed to test the hypothesis that catecholamines can cause the release of ACTH in vivo by the direct stimulation of beta 2-adrenergic receptors in the rat anterior pituitary. Systemic administration of a beta-adrenergic receptor agonist (-)-isoproterenol resulted in an increase in plasma ACTH levels in intact animals and in rats with transected pituitary stalks. This effect could be blocked by the beta-adrenergic receptor antagonist, propranolol, but not by the specific beta 1-adrenergic receptor antagonist, practolol. Salmefamol, a beta 2-adrenergic receptor agonist also elevated plasma ACTH levels in stalk-sectioned animals. Dexamethasone, a glucocorticoid that inhibits the synthesis and release of ACTH from the anterior pituitary but not the intermediate lobe, prevented the elevation of ACTH secretion by (-)-isoproterenol in stalk-transected rats. These data indicate that beta 2-adrenergic receptors are present on anterior pituitary cells and suggest that catecholamines can directly stimulate ACTH secretion.
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PMID:Direct stimulation of beta 2-adrenergic receptors in rat anterior pituitary induces the release of adrenocorticotropin in vivo. 631 39