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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study the role of cyclic AMP in the antilpolytic effect of the alpha-adrenergic agents methoxamine and phenylephrine in hamster epididymal adipocytes was studied. Both methozamine and phenylephrine lowered the very high levels of cyclic AMP that were produced by high concentrations of isoproterenol (10 muM) or ACTH (100 MU/ml), and partially inhibited lipolysis. When lower concentrations of isoproterenol were used, the antilipolytic effect of phenylephrine and methoxamine was still evident. Under these conditions methoxamine produced a slight suppression of cyclic AMP levels while phenylephrine increased accumulation of cyclic AMP. It follows, therefore, that the inhibition of lipolysis by the alpha agents is most likely unrelated to changes in cyclic AMP levels; in contrast, phenylephrine promoted lipolysis and increased cyclic AMP levels. When the stimulus for lipolysis was provided by methylxanthines a different picture emerged. Methoxamine antagonized lipolysis and lowered cyclic AMP levels. In the presence of propranolol, phenylephrine lowered cyclic AMP levels and suppressed methylxanthine-accelerated lipolysis. It is suggested that when methy xanthines provide the stimulus for lipolysis the antilipolytic effect of methoxamine and phenylephrine (in the presence of propranolol) may be mediated by the suppression in cyclic AMP levels.
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PMID:Inhibition of lipolysis in hamster epididymal adipocytes by selective alpha-adrenergic agents. Evidence for cyclic AMP-dependent and independent mechanisms. 9 May 27

The aim of this study was to determine whether methoxamine and barium stimulate 45Ca2+ uptake or efflux in the rat vas deferens in a manner that correlates with their contractile activity, and whether 45Ca2+ movements are inhibited by verapamil or nifedipine. Basal La(3+)-resistant (cellular) 45Ca2+ uptake was significantly greater in the epididymal half (791 +/- 27 nmol g-1) than in the prostatic half (654 +/- 14 nmol g-1) of the rat vas deferens and was unaffected by verapamil (61 microM) or nifedipine (14 microM). Methoxamine (8 microM) was without effect on 45Ca2+ uptake in either half but BaCl2 (1 mM) increased 45Ca2+ uptake by 31% in the prostatic half and by 22% in the epididymal half. The barium-induced increases in 45Ca2+ uptake were markedly reduced or abolished by verapamil (2 microM) or nifedipine (0.3 microM), which at these concentrations have no effect on the rhythmic contractions but abolish the initial small phasic contraction induced by barium. The basal rate of 45Ca2+ efflux from the intact vas deferens (into Ca2+ containing Krebs-Henseleit solution or into Ca-free Krebs-Henseleit solution +/- EGTA 0.05 mM) was not affected by verapamil (61 microM) or nifedipine (14 microM). Methoxamine (8 microM) produced a marked, transient and reversible increase in 45Ca2+ efflux into 2.5 mM CaCl2 Krebs-Henseleit in 50% of the intact vasa deferentia examined which was augmented by verapamil (61 microM). BaCl2 (1 mM) produced a small increase in 45Ca2+ efflux into Ca(2+)-containing and Ca(2+)-free Krebs-Henseleit solutions from some intact vasa deferentia and this was not inhibited by nifedipine (14 microM).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of methoxamine and barium on 45Ca2+ fluxes in the rat vas deferens. 149 62

Insertion of Silastic rods containing the directly acting sympathomimetic drug, methoxamine, adjacent to the epididymis of rats caused a temporary reduction in fertility with no loss of ability to mate. This effect lasted up to 3 weeks. At the time of the maximal antifertility action (3-7 days after insertion), the number of spermatozoa in the ejaculate fell to almost zero, and there was a reduction in the total number of spermatozoa in the epididymis resulting from a significant drop in the number present in the cauda. Methoxamine also caused immotility and decapitation of the remaining epididymal spermatozoa. The indirectly acting sympathomimetics, tyramine and norephedrine, did not affect fertility. It is postulated that methoxamine acts to induce infertility principally by bringing about a reduction of sperm numbers in the ejaculate. This could have been produced either by a failure of the vas and cauda to contract normally at copulation or because the sperm store in the cauda had fallen below a critical threshold level.
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PMID:Effect of local application of sympathomimetic drugs to the epididymis on fertility in rats. 735 77