Differential Effects of Fluoronorepinephrines on Phosphatidylinositol Turnover in Rat Pinealocytes |
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| Authors: | George Hauser Kenneth L. Kirk Joe M. Parks |
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| Affiliation: | Ralph Lowell Laboratories, McLean Hospital, Belmont, Department of Biological Chemistry, Harvard Medical School, Boston, Massachusetts, U.S.A.;Laboratory of Chemistry, National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, U.S.A. |
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| Abstract: | (+/-)-Norepinephrines (NAs), substituted with fluorine at positions 2, 5, and 6 of the ring, were compared with the unsubstituted compound with respect to their capacity for eliciting increased incorporation of [32P]orthophosphate into phosphatidylinositol of pinealocytes. 5F-NA and 6F-NA were approximately equipotent with NA, whereas 2F-NA required a higher concentration and gave lower maximum stimulation. Inhibition of these effects by prazosin confirmed the participation of alpha 1-adrenergic receptors. The results are comparable with those reported for alpha 1-adrenergic receptor-mediated events in other systems and different from the beta-adrenergic receptor-mediated elevation of cyclic AMP in pinealocytes. These and earlier results emphasize the importance of the hydroxyl group at position 3 of the ring and at the beta-position of the side chain in catecholamine activation of the pineal alpha-adrenergic receptors, which are involved in alterations of phospholipid metabolism. |
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| Keywords: | Phosphatidylinositol α1 Adrenergic receptors Norepinephrine analogs Pinealocytes |
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