Phospholipid source and molecular species composition of 1,2-diacylglycerol in agonist-stimulated rat cardiomyocytes.
Cardiovasc Res
; 40(1): 182-90, 1998 Oct.
Article
en En
| MEDLINE
| ID: mdl-9876331
ABSTRACT
OBJECTIVE:
The aim was to investigate the consequences of simultaneous stimulation of phospholipase C and D by agonists for the molecular species composition of 1,2-diacylglycerol and phospholipids in cardiomyocytes.METHODS:
Serum-free cultured neonatal rat cardiomyocytes were stimulated by endothelin-1, phenylephrine or phorbolester. The molecular species of 1,2-diacylglycerol (in mol%) and those derived from phosphatidylcholine and phosphatidylinositol were analyzed by high-performance liquid chromatography and their absolute total concentration (nmol per dish) by gas-liquid chromatography. Phospholipids were labelled with [14C]glycerol or double-labelled with [14C]160 and [3H]204n6 for measurements of respectively, the amount of or relative rate of label incorporation into 1,2-diacylglycerol.RESULTS:
The major molecular species of 1,2-diacylglycerol in unstimulated cells was found to be 180/204 (57 mol%). The same species was observed predominantly in phosphatidylinositol (73 mol% compared to 11 mol% in phosphatidylcholine). A significant decrease (about 10 mol%) was found for the 180/204 species of 1,2-diacylglycerol during stimulation (10-40 min) with endothelin-1 or phorbolester, but not phenylephrine. The results of the double-labelling experiments were consistent with the latterfinding:
the ratio [3H]204 over [14C]160 in 1,2-diacylglycerol decreased from 1.70 in the control to 1.40 during 10-min endothelin-1 or phorbolester stimulation, but not during phenylephrine stimulation. The [14C]glycerol incorporation into 1,2-diacylglycerol remained relatively constant under agonist-stimulated conditions as did the total concentration of 1,2-diacylglycerol.CONCLUSIONS:
1,2-Diacylglycerol present in unstimulated cardiomyocytes is likely derived from phosphatidylinositol. During stimulation with endothelin-1 and phorbolester, but not phenylephrine, phosphatidylcholine becomes an increasingly important source for 1,2-diacylglycerol due to sustained activation of phospholipase D. The 1,2-diacylglycerol level remains relatively constant during agonist stimulation which strongly indicates that particular molecular species of 1,2-diacylglycerol more than its total concentration determine the activation of protein kinase C isoenzymes.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosfolípidos
/
Agonistas alfa-Adrenérgicos
/
Diglicéridos
/
Miocardio
Límite:
Animals
Idioma:
En
Revista:
Cardiovasc Res
Año:
1998
Tipo del documento:
Article
País de afiliación:
Países Bajos