Boim M A, Ajzen H, Ramos O L, Schor N
Nephrology Division, Escola Paulista de Medicina, Sao Paulo, Brasil.
Kidney Int. 1992 Sep;42(3):567-72. doi: 10.1038/ki.1992.320.
The effects of total food deprivation on renal function were evaluated in normal Munich-Wistar rats submitted to starvation (S) periods of two to eight days (Groups S2 to S8). A prompt and sustained decrease in renal plasma flow (RPF) and an increase in total renal vascular resistance (TRVR) were observed after the second day, together with a gradual decrease in glomerular filtration rate (GFR) until the fourth day (40% in the S4 group, P less than 0.05). After this period, a spontaneous and progressive increase in GFR occurred in spite of continuing low RPF and high TRVR. Glomerular hemodynamics were evaluated in additional animals from groups S4 and S7. As observed for whole kidney GFR, mean single nephron (SN) GFR was reduced in group S4, but not in group S7. The decline in SNGFR in S4 was the result of a decline (approximately 40%) in glomerular plasma flow rate (QA) and glomerular capillary hydraulic pressure (PGC), due to a predominant increase (approximately 60%) in afferent arteriolar resistance. In S7, SNGFR and its determinants did not differ from the control. Angiotensin II (Ang II), prostaglandin (but not thromboxane A2, TxA2) inhibition blunted the alterations in whole kidney function observed in S4. Conversely in S7, the inhibition of vasoconstrictor agents (Ang II and TxA2) did not normalize GFR, suggesting that the intrarenal vasoconstriction could be an important factor to maintain GFR after a prolonged period of starvation.(ABSTRACT TRUNCATED AT 250 WORDS)
在正常的慕尼黑-威斯塔大鼠中，评估了长达两到八天饥饿期（S组，即S2至S8组）的完全食物剥夺对肾功能的影响。第二天后观察到肾血浆流量（RPF）迅速且持续下降，总肾血管阻力（TRVR）增加，同时肾小球滤过率（GFR）逐渐下降，直至第四天（S4组下降40%，P<0.05）。在此之后，尽管RPF持续较低且TRVR较高，但GFR仍出现自发且渐进性增加。对S4组和S7组的其他动物进行了肾小球血流动力学评估。如全肾GFR所示，S4组单个肾单位（SN）的平均GFR降低，但S7组未降低。S4组SNGFR的下降是由于肾小球血浆流速（QA）和肾小球毛细血管液压（PGC）下降（约40%），这是由于入球小动脉阻力显著增加（约60%）所致。在S7组中，SNGFR及其决定因素与对照组无差异。血管紧张素II（Ang II）、前列腺素（而非血栓素A2，TxA2）抑制作用减弱了S4组中观察到的全肾功能改变。相反，在S7组中，血管收缩剂（Ang II和TxA2）的抑制并未使GFR恢复正常，这表明长期饥饿后肾内血管收缩可能是维持GFR的重要因素。（摘要截断于250字）
