Activation of phospholipase D by endothelin-1 in rat myometrium. Role of calcium and protein kinase C.
In rat myometrium labeled with [3H]myristic acid, endothelin (ET)-1 via ET(A) receptors stimulated, in the presence of 0.3% butanol, the formation of [3H]phosphatidylbutanol ([3H]PBut) as a result of phospholipase D activity. Fluoroaluminates increased [3H]PBut generation, which indicated that a heterotrimeric G protein was involved. The ET-1 effect was insensitive to pertussis toxin and was rapidly desensitized. The calcium ionophore ionomycin as well as 4beta-phorbol 12-myristate-13-acetate and 4beta-phorbol 12,13-dibutyrate also stimulated [3H]P-But production. Protein kinase C (PKC) inhibition, particularly with Ro-31-8220, and down-regulation of PKC by 4beta-phorbol 12-myristate-13-acetate, abrogated 4beta-phorbol 12,13-dibutyrate responses but partially reduced (50%) ET-1 and ionomycin stimulatory effects. [3H]PBut production induced by ionomycin depended on Ca++ influx, whereas that induced by 4beta-phorbol 12,13-dibutyrate did not. Decrease of extracellular Ca++ partially reduced (60%) ET-1 stimulation that was additionally attenuated (75%) by chelerythrine, a PKC inhibitor. The data indicate that in myometrium, phospholipase D was activated by PKC and Ca++, which both contribute at least partially to ET-1-mediated phospholipase D activation.
Naze
S
S
Endocrinologie et Régulations Cellulaires, CNRS URA 1131, Université Paris Sud, Orsay, France.
Le Stunff
H
H
Dokhac
L
L
Thomas
G
G
Harbon
S
S
D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D019332:Endothelin-1 / Q000494:pharmacology*; D004789:Enzyme Activation; D005260:Female; D020404:Glycerophospholipids; D009215:Myometrium / Q000201:enzymology*; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology; D010712:Phosphatidic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000187:drug effects* / Q000378:metabolism; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D019332:Endothelin-1; D020404:Glycerophospholipids; D009227:Myristic Acids; D010456:Peptides, Cyclic; D010712:Phosphatidic Acids; C068564:phosphatidylbutanol; D019814:Myristic Acid; D011493:Protein Kinase C; D010739:Phospholipase D; D001839:Bombesin; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D002118:Calcium