Evidence for receptor-linked activation of phospholipase D in rat parotid glands. Stimulation by carbamylcholine, PMA and calcium.
In order to test if phospholipase D (PLD) activity exists in the rat parotid gland, we took advantage of the fact that, in the presence of ethanol, PLD generates phosphatidylethanol (PEth) via a transphosphatidylation reaction. Lipid extracts of parotid acini prelabelled with [3H]myristic acid were analyzed by thin layer chromatography to determine [3H]phosphatidylethanol ([3H]PEth) formation. Carbamylcholine (1 mM) stimulated [3H]PEth formation in the presence of 2% ethanol, this effect was completely inhibited by atropine (10 microM). PMA (0.1-1 microM) and ionomycine (10 microM) also caused [3H]PEth generation. We conclude that a phospholipase D activity is present in the rat parotid gland and is regulated by muscarinic cholinergic receptors. Protein kinase C and calcium could also modulate this activity. This report provides the first evidence for the existence and receptor-linked regulation of phospholipase D in an exocrine gland, the rat parotid gland.
Guillemain
I
I
Laboratoire de Biochimie des Transports Cellulaires, CNRS URA 1116, Université Paris-Sud, Orsay, France.
Rossignol
B
B
D000818:Animals; D002855:Chromatography, Thin Layer; D004789:Enzyme Activation; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D010306:Parotid Gland / Q000201:enzymology*; D010739:Phospholipase D / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000378:metabolism*; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007476:Ionophores; D011976:Receptors, Muscarinic; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate