Aims: This study evaluates the effect of bilateral nephrectomy on the gastric emptying of a liquid meal.
Methods: Male rats were submitted under anesthesia to cervical vessels cannulation and bilateral lumbar incision, followed or not by nephrectomy. Next day, they were gavage fed (1.5 mL) with phenol red (0.5gmL(-1)) in 5% glucose solution and sacrificed 0,10, 20,30 or 45 min later. A blood sample was obtained for biochemical analysis while gastric dye retention was determined by spectrophotometry. Data (mean +/- SEM) were compared by ANOVA and Student-Newman-Keuls tests.
Results: Gastric emptying values from nephrectomy group at 10,20,30 and 45 min were lower (P < 0.05) than those of sham-operated animals (22.0 +/- 4.0 vs. 38.9 +/- 6.1%, 34.1 +/- 1.4 vs. 66.9 +/- 1.3%, 45.5 +/- 6.1 vs. 64.9 +/- 5.4% and 59.7 +/- 2.4 vs. 81.5 +/- 4.0%, respectively). Mean arterial pressure, blood volume, serum osmolarity, urea, creatinine and potassium values were higher (P < 0.05) in nephrectomy group than in sham-operated animals (143.3 +/- 2.7 vs. 100.5 +/- 4.1 mmHg, 15.7 +/- 0.9 vs. 8.9 +/- 1.1 mL 100 g(-1), 344.0 +/- 10.8 vs. 299.4 +/- 1.3 mOsm KgH2O(-1), 344.0 +/- 33.7 vs. 47.0 +/- 2.8mg dL(-1), 3.6 +/- 0.3 vs. 1.1 +/- 0.1 mg dL(-1), 6.4 +/- 0.7 vs. 3.7 +/- 0.2 mEq L(-1), respectively). The plasmatic Na+ values did not change (139.3 +/- 2.0 in sham-operation vs. 123.0 +/- 7.5 mEq L(-1) in nephrectomy).
Conclusion: Acute loss of kidney function markedly delays the gastric emptying rates, which could be involved in gastrointestinal dysmotility complaints seen after renal failure.