Enhanced phosphatidylinositol labelling in rat parotid fragments exposed to alpha-adrenergic stimulation.
1. Adrenergic agonists provoke a marked increase in labelling of phosphatidylinositol in fragments of rat parotid gland. 2. Adrenaline and phenylephrine (an adrenergic alpha-agonist) are effective stimulants, but isoprenaline (an adrenergic beta-agonist) is relatively ineffective. 3. The response evoked by phenylephrine or adrenaline is prevented by prior incubation of the tissue with phenoxybenzamine (an alpha-receptor blocking agent), but not by prior incubation with pindolol (a beta-receptor blocking agent). 4. Adrenergic stimulation of phosphatidylinositol metabolism in parotid gland is therefore mediated through alpha-receptors, in common with the adrenaline-induced K(+) efflux. It is not linked to enzyme secretion, which is triggered by stimulation of beta-receptors. 5. It is suggested that the stimulation of phospholipid metabolism that occurs in several other tissues in the presence of adrenaline or noradrenaline may also involve alpha-receptors.
D000818:Animals; D001692:Biological Transport; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D010643:Phenoxybenzamine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology*; D010713:Phosphatidylcholines / Q000096:biosynthesis; D010714:Phosphatidylethanolamines / Q000096:biosynthesis; D010716:Phosphatidylinositols / Q000096:biosynthesis*; D010761:Phosphorus Radioisotopes; D010869:Pindolol / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D013997:Time Factors
D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010716:Phosphatidylinositols; D010761:Phosphorus Radioisotopes; D010643:Phenoxybenzamine; D010656:Phenylephrine; D010869:Pindolol; D007545:Isoproterenol; D011188:Potassium; D004837:Epinephrine