Baylis C, Foulks C, Samsell L, Engels K
Department of Physiology, West Virginia University, Morgantown 26506.
Clin Exp Hypertens A. 1991;13(6-7):1153-67. doi: 10.3109/10641969109042119.
Renal clearance studies were conducted in conscious, chronically catheterized obese and lean Zucker rats to investigate the natriuretic responses to i) acute IV infusion of isotonic NaCl = 5% of total body weight and ii) IV infusion of alpha rat atrial natriuretic peptide (ANP) in a dose of 300 ng/kg/min. In the baseline state, arterial blood pressure (BP) was significantly higher in obese vs lean rats. Absolute values of GFR and sodium excretion were similar but lower in obese vs lean rats when factored for body weight. In the 2 h period during and after NaCl infusion, obese rats showed a greater natriuresis vs lean while BP rose significantly and similarly. ANP infusion was natriuretic in obese rats but had no effect on lean rats. ANP lowered BP in both groups but BP remained higher in obese vs lean rats at all times. These studies show that in the chronic, unstressed preparation the 6-8 month old, female Zucker obese rat has a higher BP vs the 6-8 month old lean Zucker. The short term natriuretic response to either a NaCl load or ANP infusion is greater in obese vs lean Zuckers and the depressor response to ANP is intact in obese Zuckers. Thus the higher BP in this model of obesity is unlikely to be due to either a defective response to ANP or to a defect in the renal response to acute sodium challenge.
在清醒、长期插管的肥胖和瘦素 Zucker 大鼠中进行了肾清除率研究，以调查对以下情况的利钠反应：i）急性静脉输注等渗 NaCl（占总体重的 5%）和 ii）静脉输注剂量为 300 ng/kg/min 的 α 大鼠心房利钠肽（ANP）。在基线状态下，肥胖大鼠的动脉血压（BP）明显高于瘦素大鼠。肾小球滤过率（GFR）和钠排泄的绝对值相似，但按体重计算时，肥胖大鼠低于瘦素大鼠。在输注 NaCl 期间及之后的 2 小时内，肥胖大鼠与瘦素大鼠相比表现出更大的利钠作用，而血压显著且相似地升高。ANP 输注对肥胖大鼠有利钠作用，但对瘦素大鼠无影响。ANP 使两组血压均降低，但肥胖大鼠的血压在所有时间均高于瘦素大鼠。这些研究表明，在慢性、无应激的实验准备中，6 - 8 个月大的雌性 Zucker 肥胖大鼠与 6 - 8 个月大的瘦素 Zucker 大鼠相比血压更高。肥胖 Zucker 大鼠对 NaCl 负荷或 ANP 输注的短期利钠反应大于瘦素 Zucker 大鼠，且肥胖 Zucker 大鼠对 ANP 的降压反应是完整的。因此，在这种肥胖模型中血压升高不太可能是由于对 ANP 的反应缺陷或对急性钠挑战的肾反应缺陷所致。
