Mikropunktionsversuche zum Verhalten der PAH-Konzentration im Vasa recta-Blut der Goldhamsterniere

✍ Scribed by J. Schnermann; K. Thurau

• Publisher: Springer
• Year: 1965
• Tongue: English
• Weight: 638 KB
• Volume: 283
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00363187

✦ Synopsis

In golden hamsters PAN concentration was determined in samples of renal vasa recta blood (VR1)Alt) obtained by micropuncture. Peripheral plasma PAI-I concentrations (PpAt{) ranged between 2 and 10 mg-°/0 and EpAlt between 0.32 and 0.85 with a mean of 0.61. VRpAI~ during antidiuresis was found to be 4--13 times peripheral plasma concentration (VR/PpAH = 4-13) with a mean of 8. This ratio was the same whether the papilla was covered with light mineral oil or isotonic saline. [PAH] in final urine (CDpAlt) as collected from the Duetus Bellini averaged 4 times that of VRpA~. This ratio increases to 5.6 when correction is applied to account for the protein bound fraction of PAI-I, which was measured to be 320/0 . During NHtCI° or mannitol diuresis VI%/PI~AtI was reduced to 1.9, CD/PpAt~ corrected for protein binding to 2.5. Samples taken from different levels of the papilla revealed always a higher VR/PpAtI-ratio in samples obtained closer to the tip. The hematoerits in vasa recta samples were between 0.19 and 0.3.

The results are taken to indicate that PAH enters the vasa recta blood by backdiffusion from medullary urine and is trapped by counter current diffusion between ascending and descending limbs of vasa recta. The calculated amount of PAH added to vasa recta blood by means of baekdiffusion is equivMent to at least 4°/o of total PAH delivered to the kidney by arterial inflow. This amount leaves the kidney by way of the renal vein. Die renale Ausscheidung der p-Aminohippurs/~ure (PAH) erfolgt beim Warmbl/iter im wesentlichen fiber eine tubuli~re Sekretion im proximalen Tefl des Nephrons%S, 17. Das peritubul~re Blur der Nierenrinde wird dadurch fast vollstitndig yon der PAH extrahiert. Im Gegensatz dazu wird ftir das Blur, das dureh das Nierenmark ttiegt, angenommen, dab es mit sekretorischem Tubulusepithel nieht in Berfihrung kommt und daher mit arterie]ler PAH-Konzentration das Mark perfundiert21, 23. Mit dieser Vorsteilung stimmen Untersuehungen fiber den anatomisehen * Mit Unterstfitzung der Deutschen Forschungsgemeinschaft. ** Auszugsweise vorgetragen auf dem III. Symposium der Gesellschaft fiir Nephrologie, Berlin 1964.