Expression of Endothelin-1 and Adrenomedullin Was Not Altered by Leptin or Resistin in Bovine Brain Microvascular Endothelial Cells

Abstract

Hypertension frequently occurs in obese subjects. It has been reported that leptin and resistin induce endothelin-1 expression in vascular endothelial cells. Altered function of brain microvascular endothelial cells may be related to increased occurrences of stroke in hypertensive patients. In the present study, we therefore studied the effects of leptin and resistin on the expression of endothelin-1 and adrenomedullin in bovine brain microvascular endothelial cells. Northern blot analysis showed that leptin (10(-10)-10(-8) mol/l), resistin (10(-10)-10(-8) mol/l) or a combination of leptin and resistin (10(-8) mol/l for each) had no significant effects on the expression of endothelin-1 mRNA or adrenomedullin mRNA in cultured bovine brain microvascular endothelial cells. On the other hand, hypoxia induced, and tumor necrosis factor-alpha (10 ng/ml) decreased, the expression levels of endothelin-1 and adrenomedullin mRNAs, indicating that the bovine brain microvascular endothelial cells were able to respond to hypoxia and tumor necrosis factor-alpha. Consistent with the results of Northern blot analysis, immunoreactive endothelin and immunoreactive adrenomedullin concentrations in the medium were not significantly changed by the treatment with leptin, resistin, or a combination of leptin and resistin. The present study thus showed that neither leptin nor resistin affects the expression of endothelin-1 or adrenomedullin in bovine brain microvascular endothelial cells.