The Renal Excretion of Nitrogen Containing Metabolites

Schmidt‐Nielsen, Bodil; Lassiter, William E.; Roch-Ramel, F; Chométy, Françoise; Peters, G.; Truniger, B; Grossmann, Dieter; Gebauer, Leonie; Nolte, A; Kopp, K. F.; Kramer, Kürt; Reinhardt, H. W.; Ellinghaus, K.; Klose, Holger; Deetjen, P.; Ullrich, Karl Julius; Zöllner, N.; Schirmeister, J; Man, N. K.; Hallauer, W; Moeller, J; Masbernard, A; Hiltenbrand, C; Memin, Y; Pitts, Robert F.; Brandis, M.; Braun-Schubert, G.; Gertz, K. H.; Renner, D.; Heintz, R.; Federlin, K.; F, Sorge; Prát, V; Koníčková, Ludmila; Ritzerfeld, W; Losse, H; Walther, D; Göggel, K. H.; Hübner, Karl; Schoeppe, W.; Blumberg, A; Kluthe, R.; Quirin, H.; Heinze, V.; Tourkantonis, A.; Zollinger, Hans Ulrich; Heidland, A.; Klütsch, K.; Teratani, Takuma; Scheitza, E; Schäfer, H.; Schäfer, A.; Gottesleben, A.; Prill, A; Quellhorst, E; Volles, E.; Scheler, F.; Campanacci, L; Guarnieri, Gabriella; Siliprandi, N.; Fiaschi, E; Keller, H. E.; Kramer, H. J.; Jutzler, G. A.; Doenecke, Detlef; Traut, G; Müting, D; Griebel, L.; Günther, Frank; Friedrich, Wolfgang; Lackenschweiger, A.; Weissel, W; Zimmermann, E.

doi:10.1007/978-3-642-87957-9_1

Cited by 3 publications

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“…The osmolality of urine from the right kidney increased after urea infusion by 59%, reflecting an increase in the concentration of both urea and nonurea solute, in accord with published findings (1)(2)(3)(4)(5)(6). We have previously observed (13,16,21), as have others (22)(23)(24), that exposure of the papillary tip compromises the ability to elaborate a concentrated urine. (Compare urinary osmolality from right and left kidneys in Tables II and III.).…”

Section: Effect Of Urea On Urinary Concentrating Mechanism In Proteinsupporting

confidence: 91%

The effect of urea infusion on the urinary concentrating mechanism in protein-depleted rats.

Pennell¹,

Sanjana²,

Frey³

et al. 1975

J. Clin. Invest.

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A B S T R A C T To explore the role of urea in the urinary concentrating mechanism, the contents of vasa recta, Henle's descending limbs and collecting ducts were sampled by micropuncture of the renal papilla before and after infusion of urea in 10 protein-depleted rats. Eight protein-depleted rats not given urea were similarly studied as a control group. After urea administration, osmolality and the concentrations of urea and nonurea solute of urine from both exposed and contralateral kidney increased significantly. The osmolality and urea concentration of fluid from the end of Henle's descending limb and vasa recta plasma and the tubule fluid-to-plasma inulin ratio in the end-descending limb all increased significantly after urea infusion. We interpret these observations to indicate that urea enhances urinary concentration by increasing the abstraction of water from the juxtamedullary nephron (presumably the descending limb), in agreement with the prediction of recent passive models of the urinary concentrating mechanism. However, the concentration of urea in fluid from the descending limb after urea infusion was high (261±31 mM) and the difference in sodium concentration between descending limb fluid and vasa recta was small and statistically insignificant.

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Section: Effect Of Urea On Urinary Concentrating Mechanism In Proteinsupporting

confidence: 91%

The effect of urea infusion on the urinary concentrating mechanism in protein-depleted rats.

Pennell¹,

Sanjana²,

Frey³

et al. 1975

J. Clin. Invest.

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Anatomy of the renal pelvis in the hamster

Lacy

Schmidt‐Nielsen

1979

Am. J. Anat.

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The hamster renal pelvis has been studied by means of low-power light microscopy, scanning electron microscopy and morphometric analyses. The results of this study are highly suggestive that the contact of pelvic urine with the other medulla as well as with the inner medulla may be an important aspect of final urine formation. The outer medulla constituted nearly 50% of the total pelvic surface area, with the inner stripe of the outer medulla more than twice the pelvic surface area of the outer stripe of the outer medulla. The large outer medullary pelvic surface area was accounted for by the elaboration of the upper pelvic walls into peripelvic columns, opercula ("secondary pyramids"), fornices and secondary pouches. A thin simple-squamous to low cuboidal pelvic epithelium separated pelvic urine from outer medullary parenchyma. The inner medulla which constituted about one quarter of the total pelvic surface area was covered by a cuboidal to columnar pelvic epithelium which appeared morphologically similar to the papillary collecting duct epithelium. Tubules and capillaries of the inner medulla did not appear as closely juxtaposed to the pelvic epithelium as did those of the outer medulla. Cortical tissue comprised only 11.7% of the total pelvic surface area and was covered by transitional epithelium similar to that of ureter and bladder. The previously reported impermeability of this epithelium suggests that pelvic urine contact with the cortex is unimportant in final urine formation. The rich layer of smooth muscle under the transitional epithelium probably functions to move urine into and out of the pelvis during pelvic peristalsis, which has been observed in vivo.

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