Metabolitkonzentrationen in der Niere und Paraaminohippursäureclearance nach akuter Ischämie und in der Erholung nach Ischämie

Thorn, W.; Liemann, F.; Wichert, P. v.

doi:10.1007/bf00363052

Cited by 32 publications

(12 citation statements)

References 26 publications

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Section: Introductionmentioning

confidence: 99%

“…One of the earliest manifestations of renal ischemia is a rapid decrease in cortical ATP content (5)(6)(7), which is depleted by 60-90% within minutes of the initiation of ischemia (5)(6)(7). Initially, the decreased ATP appears as an accumulation ofAMP (5)(6)(7)(8). The AMP is further hydrolyzed in a slower reaction to mainly hypoxanthine (HX)' in the rabbit (7,8) and a mixture ofHX and xanthine in the rat (5,6).…”

Section: Introductionmentioning

confidence: 99%

“…Initially, the decreased ATP appears as an accumulation ofAMP (5)(6)(7)(8). The AMP is further hydrolyzed in a slower reaction to mainly hypoxanthine (HX)' in the rabbit (7,8) and a mixture ofHX and xanthine in the rat (5,6). Therefore, as the ischemic time is increased, there is a progressive degradation of adenine nucleotides in the cells reaching 75-90% loss after 45-60 min (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

“…The AMP is further hydrolyzed in a slower reaction to mainly hypoxanthine (HX)' in the rabbit (7,8) and a mixture ofHX and xanthine in the rat (5,6). Therefore, as the ischemic time is increased, there is a progressive degradation of adenine nucleotides in the cells reaching 75-90% loss after 45-60 min (5)(6)(7)(8). During reoxygenation, resynthesis of ATP from AMP is fast, and therefore, the cells can rapidly recover their ATP contents when the total adenylate loss is minor (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, as the ischemic time is increased, there is a progressive degradation of adenine nucleotides in the cells reaching 75-90% loss after 45-60 min (5)(6)(7)(8). During reoxygenation, resynthesis of ATP from AMP is fast, and therefore, the cells can rapidly recover their ATP contents when the total adenylate loss is minor (5)(6)(7)(8). Conversely, resynthesis of ATP from HX is very slow (7,9).…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms whereby exogenous adenine nucleotides improve rabbit renal proximal function during and after anoxia.

Mandel

Takano²,

Soltoff³

et al. 1988

J. Clin. Invest.

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When a suspension of rabbit proximal tubules is subjected to anoxia, ATP falls by 80-90% during 40 min of anoxia, and upon reoxygenation (reox) the cells only recover 25-50% of their initial ATP. Addition of Mg-ATP (magnesium chloridetreated ATP), Mg-ADP, or Mg-AMP (five aliquots of 200 nmol/ml added 10 min apart) during anoxia causes complete recovery of ATP levels, and respiratory and transport function after 40 min of reox. Similar additions of adenosine (ADO), or inosine (INO), or Mg-ATP only during reox are less effective. Lactate dehydrogenase (LDH) release after 40 min of anoxia is 30-40% under control conditions, only 10-15% when adenine nucleotides or ADO are added during anoxia, and 20% when INO is added, suggesting that these additions may stabilize the plasma membrane during anoxia and help preserve cellular integrity. During reox, recovery may depend on the entry of ATP precursors and, therefore, we explored the mechanism whereby exogenous ATP increases the intracellular ATP content. Additions of Mg-ATP, Mg-ADP, or Mg-AMP to continuously oxygenated tubules increase cellular ATP content three-to fourfold in 1 h. The added ATP and ADP are rapidly degraded to AMP, and more slowly to ADO, INO, and hypoxanthine. Furthermore, the ATP-induced increase in cellular ATP is abolished by the exogenous addition of adenosine deaminase, which converts extracellular ADO to INO. These results suggest that the increase in cellular ATP requires extracellular ADO. The ADO obtained from the breakdown of AMP may be preferentially transported into the renal cells to be resynthesized into cellular AMP and ATP.

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