Low density lipoprotein enhances the cellular action of arginine vasopressin in rat glomerular mesangial cells in culture.
AUTOR(ES)
Ishikawa, S
RESUMO
The present study was undertaken to determine whether low density lipoprotein (LDL) modulates the cellular action of arginine vasopressin (AVP) in rat glomerular mesangial cells in culture. AVP increased cellular free calcium ([Ca2+]i) in a dose-dependent manner. When cells were preincubated for 24 h with 10 microgram/ml LDL, the 1 x 10(-7) M AVP-mobilized [Ca2+]i was 874 nM, a value significantly greater than that of 375 nM in the intact cells. AVP caused a biphasic change in cellular pH (pHi), namely, an early acidification followed by a sustained alkalinization, and the change in pHi produced by AVP was also enhanced by LDL. AVP stimulated a 2.2-fold increase in [3H]thymidine incorporation, an effect significantly greater in the presence of 10 micrograms/ml LDL. Furthermore, 1 x 10(-7) M AVP significantly activated mitogen-activated protein kinase from 14.0 to 24.5 pmol/mg protein. Such an activation was significantly enhanced by the LDL pretreatment. Both [3H]thymide incorporation and mitogen-activated protein kinase were not altered by 10 micrograms/ml LDL. [3H]AVP receptor binding was not affected by the LDL pretreatment. 1 x 10(-7) M AVP increased inositol trisphosphate production by 1.9-fold, an effect significantly greater in the presence of LDL. These results indicate that LDL enhances the cellular action of AVP and the AVP-stimulated cellular proliferation in glomerular mesangial cells. A site of action of LDL is the hydrolysis of phosphatidylinositol.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=294522Documentos Relacionados
- Prostaglandin synthesis by rat glomerular mesangial cells in culture. Effects of angiotensin II and arginine vasopressin.
- Contraction of Cultured Rat Glomerular Cells of Apparent Mesangial Origin after Stimulation with Angiotensin II and Arginine Vasopressin
- Iron and copper promote modification of low density lipoprotein by human arterial smooth muscle cells in culture.
- Production of platelet-derived growth factorlike protein by rat mesangial cells in culture.
- Lipoprotein lipase enhances the binding of chylomicrons to low density lipoprotein receptor-related protein.