Urea recycling from the renal pelvis in sheep: A study with ( sup 14 C)urea

Journal Article · Tue May 01 00:00:00 EDT 1990 · American Journal of Physiology; (USA)

OSTI ID:6749103

Cirio, A; Boivin, R ^[1]

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1. Ecole Nationale Veterinaire de Lyon, Marcy l'Etoile (France)

To test the hypothesis that urea can be recycled from the renal pelvis, (14C)urea diluted in native urine (1 microCi/ml) was perfused (0.5 ml/min) into one of the pelvises of sheep fed either normal (NP) or low (LP)-protein diets. Blood samples were obtained from the ipsilateral renal vein and from the carotid artery throughout the perfusions. 14C activity determinations in urine and plasma demonstrated a flux of (14C)urea from the pelvis to renal vein blood (40,000 in NP and 130,000 disintegrations/min in LP sheep, P less than 0.01). The corresponding flux of native urea was only 1.5 times higher in NP than in LP sheep (6.8 +/- 1.1 vs. 4.7 +/- 2.9 mumol/min, not significant) despite their 8 times higher urinary concentration of urea. The fraction of filtered urea that was reabsorbed in the pelvis was larger in LP sheep (7.5 +/- 3.7 vs. 1.9 +/- 0.7% in NP sheep, P less than 0.05). A fraction of urea is thus actually recycled from the renal pelvis in sheep, and this pelvic retention is enhanced in LP animals. The importance of this phenomenon in the nitrogen economy is discussed.

• OSTI ID: 6749103
• Journal Information: American Journal of Physiology; (USA), Vol. 258; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
UREA
MEMBRANE TRANSPORT
ABSORPTION
BLOOD
CARBON 14 COMPOUNDS
DIET
KIDNEYS
PERFUSED ORGANS
PHYSIOLOGY
PROTEINS
SHEEP
TRACER TECHNIQUES
URINE
AMIDES
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
CARBONIC ACID DERIVATIVES
DOMESTIC ANIMALS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
RUMINANTS
VERTEBRATES
WASTES
551001* - Physiological Systems- Tracer Techniques