ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The α-adrenergic agonists phenylephrine and methoxamine, at concentrations that have little effect on pineal N-acetyltransferase activity, markedly enhance stimulation of this enzyme by vasoactive intestinal polypeptide (VIP). This augmentation can be blocked by the α1-adrenergic antagonists phenoxybenzamine and prazosin and, at 10 but not 1 μM, by the α2-antagonist yohimbine. The time course for VIP stimulation is not altered by concomitant α-adrenergic stimulation. Augmented activity does not require concomitant α-adrenergic stimulation, but α-adrenergic agonists must be present for augmentation to be maintained. Phorbol 12, 13-diacetate or -dibutyrate but not 4a-phorbol can substitute for phenylephrine, a finding suggesting that protein kinase C is involved in the augmentation. These results are, in general, analogous to α-adrenergic magnification of N-acetyltransferase induction by β-adrenergic agonists.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1987.tb00965.x
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