engleski

ENDOTHELIN STIMULATES CORTICAL 1,2-DIACYLGLYCEROL PRODUCTION DURING INITIATION OF COMPENSATORY RENAL GROWTH IN THE RAT

Presence of endothelin (ET) receptors in the rat proximal tubule was recently demonstrated. We assessed the role of ET in the stimulation of 1,2-diacylglycerol (DAG) production in cortical plasma membranes (CM) and brush-border membranes (BBM) isolated from renal cortical slices during initiation of compensatory renal growth (CRG) in the rat. In the CM, DAG content increased after 20 min. of CRG (490ą12 pmol/mg prot.) compared to the shamUNI CM (202ą5 pmol/mg prot.). Bosentan, a nonselective ETA,B antagonist, given i.v. prior to UNI, prevented this increment in DAG (217ą9 pmol/mg prot.). In BBM, DAG level was higher in the membranes isolated from slices preincubated with 25% UNI-plasma, obtained after 20 min. CRG (683ą8 pmol/mg prot.), than in the membranes isolated from shamUNI-plasma-pretreated slices (314ą26 pmol/mg prot.). Bosentan prevented this increment in DAG (290ą42 pmol/mg prot.). Cortical tissue bigET-1/ET-1 concentration was higher in 20 min.UNI (443ą12 fmol/g tissue), than in removed (267ą9 fmol/g tissue) kidneys. Stimulation of cortical DAG formation is the earliest signalling event in the CRG. It is due to ET action through BBM receptors. This suggests that ET may participate in the initiation of CRG.

endothelin; 1;2-diacylglycerol production; initiation of compensatory growth; rat renal cortex

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