Atrial natriuretic factor, arachidonic acid metabolites and acute renal ischemia: experimental protocol in the rat

The effects of an atrial natriuretic factor (ANF) infusion upon the production of the arachidonic acid metabolites (thromboxane B2, TxB2; 6-keto-prostaglandin F1 alpha, 6-keto-PGF1 alpha, PGI2, or prostaglandins E2, PGE2) were investigated after acute renal ischemia in the rat. This experimental protocol included a right nephrectomy and a 45-min left renal artery occlusion. Fifteen minutes after declamping, blood samples were collected from the left renal venous effluent for the assay of plasmatic prostanoid concentrations. Three experimental groups were studied: group I (n = 9) sham, no ischemia-group II (n = 9) control group, 45 min of left renal ischemia, followed by a 15-min revascularization, and group III (n = 10) ANF group, a similar ischemic protocol to that in group II was used but, after declamping, synthetic Atriopeptin III was infused (0.5 micrograms/kg/min) during the 15-min of vascular reflow. Fifteen minutes after declamping, TxB2 secretion significantly increased after ischemia in the control and ANF groups: TxB2: 210 +/- 22.4 pg/ml (control group) and 234.8 +/- 25.1 pg/ml (ANF group) versus 135.8 +/- 17.8 pg/ml (sham group) (p less than 0.05 and 0.01, respectively). On the other hand, the 6-keto-PGF1 alpha plasma levels were significantly higher after ischemia in the ANF group (221 +/- 34 pg/ml) in comparison with the sham (124 +/- 24.1 pg/ml) or with the control group (116.7 +/- 12.5 pg/ml). The calculated TxB2/6-keto-PGF1 alpha ratio was therefore higher in the control group, 1.93 +/- 0.27, than in physiological conditions (sham group), 1.2 +/- 0.17.(ABSTRACT TRUNCATED AT 250 WORDS)