Role of eicosanoids of the contralateral kidney in maintenance of two-kidney, one-clip renovascular hypertension in rats

Abstract

Objective. To elucidate the role of the eicosanoids prostaglandin E₂ (PGE₂), 6-keto-prostaglandin F_1a (PGF_1a) and thromboxane B₂ (TXB₂) in the maintenance of two-kidney, one-clip renovascular hypertension in rats. Material and methods. The right renal artery was constricted by a silver clip in 63 male Sprague–Dawley rats to induce hypertension, while a sham operation was performed in 17 control rats. Six months after the induction of hypertension, nephrectomy of the clipped kidney was performed. Nephrectomy was followed by a period of high sodium intake. Blood pressure and eicosanoid excretion were measured before and after nephrectomy of the clipped kidney, as well as during high sodium intake. Results. During the chronic phase of Goldblatt hypertension, the amount of vasoconstrictive TXB₂ excreted by the contralateral kidney increased compared to that in the controls, whereas PGE₂ excretion was unaffected. Eicosanoid excretion before and after removal of the clipped kidney did not differ between post-Goldblatt hypertensive and post-Goldblatt normotensive animals. During the period of high sodium intake, PGE₂ excretion increased only in control rats, being unaltered in Goldblatt hypertensive rats. Conclusions. In the chronic phase of two-kidney, one-clip renovascular hypertension, the contralateral kidney of post-Goldblatt hypertensive and post-Goldblatt normotensive rats excretes more vasoconstrictive thromboxane in comparison to controls, whereas excretion of vasodilatory prostaglandin is not elevated. However, increased TXB₂ excretion and the absence of an increase in PGE₂ excretion from the contralateral kidney do not appear to be important for the maintenance of high blood pressure in this model of renovascular hypertension.

• Renovascular hypertension
• eicosanoid excretion
• prostaglandin E₂
• 6-keto-prostaglandin F_1a
• thromboxane B₂