Sphingosine increases inositol trisphosphate in rat parotid acinar cells by a mechanism that is independent of protein kinase C but dependent on extracellular calcium.
Cell Calcium
; 11(7): 469-75, 1990 Aug.
Article
en En
| MEDLINE
| ID: mdl-2272081
ABSTRACT
In rat parotid acinar cells prelabelled with [3H]-inositol, sphingosine stimulated the accumulation of [3H]-inositol polyphosphates. When the cells were exposed to sphingosine, [3H]-inositol trisphosphate (InsP3) was accumulated in a time- and dose-dependent manner. When the extracellular Ca2+ was chelated by 1 mM EGTA, the effect of sphingosine on InsP3 accumulation was completely inhibited. Ionophores, A23187 and ionomycin, had no significant effect on InsP3 accumulation. An inhibitor of protein kinase C, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), failed to stimulate InsP3 accumulation. In the homogenate of parotid acinar cells, InsP3 3-kinase and 5-phosphomonoesterase activities were not affected by sphingosine. These results suggest that sphingosine activates phosphoinositide turnover by a mechanism dependent upon extracellular Ca2+, but different from that of an ionophore, and independent of protein kinase C.
Buscar en Google
Banco de datos:
MEDLINE
Asunto principal:
Glándula Parótida
/
Esfingosina
/
Proteína Quinasa C
/
Inositol 1,4,5-Trifosfato
/
Calcio
Límite:
Animals
Idioma:
En
Año:
1990
Tipo del documento:
Article