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)

Steroidogenesis by Y-1 adrenal tumor cells in culture is stimulated by ATP, adenyl-5'-yl imidodiphosphate (App(NH)), adenosine 5'(beta, alpha-methylene)triphosphate (App(CH2)p), ADP, AMP, NAD, FAD, and adenosine but not by adenine or other nucleoside triphosphates. ATP, App(NH)p, App(CH2)p, and adenosine are active in the micromolar range. Like adrenocorticotropic hormone (ACTH), the onset of stimulation is immediate and occurs to the same extent. Also active are 2'- and 5'-deoxyadenosine and 2-chloroadenosine whereas adenine xyloside, L-riboside, or arabinoside have very low activity. Stimulation is accompanied by rounding of the cells. Dipyridamole, an inhibitor of adenosine transport, increased the response to low concentrations of adenosine, suggesting that adenosine acts externally. Stimulation of steroidogenesis by adenosine or phosphorylated adenosine compounds fails to occur in the presence of crystalline adenosine deaminase, and the effect of the enzyme on adenosine, ATP, or NAD stimulation is reversed by the competitive inhibitor erythro-9-[3-(nonane-2-ol)]adenine. This suggests that the enzyme acts specifically on adenosine and a requirement for the conversion of the above compounds to adenosine seems probable. The inhibition of cAMP effects by adenosine deaminase suggests that some of its effects are also mediated by conversion to adenosine. Similar stimulation is seen in I-10 Leydig tumor cells, but an ACTH-resistant mutant of Y-1 cells, called OS-3, is relatively resistant to adenosine. Adenosine and 2-chloroadenosine stimulate adenylate cyclase in membranes from Y-1 and I-10 cells at concentrations slightly greater than are effective for steroidogenesis. Other nucleosides are ineffective. Like the NH2-terminal 24 residues of adrenocorticotropic hormone (1-24 ACTH), the adenosine effect in Y-1 membranes is rapid and is on the Vmax intercept (versus ATP) and not on the Km. In contrast to steroidogenesis, adenosine is only a partial agonist for adenylate cyclase. It effect occurs in the presence of ITP, GTP, or guanyl-5'-yl imidodiphosphate (Gpp(NH)p). Theophylline inhibits adenosine-stimulated steroidogenesis. Inhibition of adenylate cyclase occurs in the same concentration range but is of the mixed type.
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PMID:Activation of steroidogenesis and adenylate cyclase by adenosine in adrenal and Leydig tumor cells. 18 24

The inhibitory effects of adenosine as well as its related analogues on the contractile response of the rat vas deferens to field stimulation were compared in the absence and in the presence of nitrobenzylthioguanosine (NBTGR), a potent adenosine uptake inhibitor. In the presence of NBTGR, the order of potency was N6-cyclohexyladenosine (CHA) greater than or equal to L-N6-phenylisopropyladenosine (L-PIA) greater than 2-chloroadenosine greater than D-N6-phenylisopropyladenosine (D-PIA) greater than or equal to adenosine greater than 2'-deoxyadenosine. The inhibitory effect of adenosine but not that of clonidine, beta-endorphin and somatostatin was blocked by 1,3-diethyl-8-phenylxanthine (DPX, pA2 = 7.2), a potent P1-purinergic antagonist. The results suggest that adenosine inhibited the electrically evoked contractions of the rat vas deferens via the activation of the A1 subtype of P1-purinergic receptors.
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PMID:Inhibitory effect of adenosine on electrically evoked contractions in the rat vas deferens: pharmacological characterization. 299 81