Mesangial cells cultured from pregnant rats display reduced reactivity to angiotensin II: the role of relaxin, nitric oxide and AT2 receptor.

Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology

PubMedID: 23207895

Carvalho LN, Cristovam PC, Passos CS, Boim MA. Mesangial cells cultured from pregnant rats display reduced reactivity to angiotensin II: the role of relaxin, nitric oxide and AT2 receptor. Cell Physiol Biochem. 2012;30(6):1456-64.
BACKGROUND/AIMS
Pregnancy is characterized by vasodilatation and increased glomerular filtration rate (GFR), despite overstimulation of the renin angiotensin system (RAS). The mesangial cells (MCs) influences GFR and when cultured from pregnant rats displays refractoriness to Ang II. We evaluated the role of relaxin (RLX) and its receptor (RXFP1), nitric oxide (NO) and the AT2 receptor in this response.

METHODS
MCs cultured from kidneys of virgin (V) and pregnant (P) Wistar rats were treated with RLX or AT2 receptor blocker PD123319 or NO synthase inhibitor L-NAME. After 24 hr, intracellular calcium concentration ([Ca]i) was recorded before and after the addition of Ang II.

RESULTS
MCs from V group expressed AT2, RLX and RXFP1, whose levels were increased in P cells. Ang II induced a 150% increase in [Ca] i in the V cells and 85% (p<0.05) in the P cells. V cells treated with RLX displayed a similar response to that observed in P cells, suggesting that RLX can modulate the reactivity of the MCs to Ang II. L-NAME and PD123319 did not interfere in this response.

CONCLUSION
Results suggest that RLX is a mediator of the refractoriness of the MCs to Ang II during pregnancy.