Coupling of albumin flux to volume flow in skin and muscles of anesthetized rats
Bovine serum albumin (BSA) labeled with /sup 131/I or /sup 125/I was injected intravenously in pentobarbital sodium-anesthetized rats, and tracer clearances into leg skin and muscles were measured over 30, 60, and 120 min. BSA labeled with the alternate tracer was used as vascular volume reference. Two minutes before injection of the tracer, a ligature was tied around one femoral vein to occlude outflow partially and raise capillary pressure in that leg. The unoccluded leg served as control. Skin and muscles of the occluded leg had variably and substantially higher water contents (delta W) than paired control tissues and slightly but consistently increased albumin clearances (CA). The delta CA/delta W, equivalent to the albumin concentration of capillary filtrate relative to plasma determined by linear regression, were as follows: leg skin 0.004 (95% confidence limits -0.001 to +0.009), muscle biceps femoris 0.005 (0.001-0.010), muscle gastrocnemius 0.011 (0.004-0.019), muscle tibialis anterior 0.016 (0.012-0.021). All these values are significantly less than 0.10, which corresponds to a reflection coefficient for serum albumin (sigma A) of 0.90. Convective coupling of albumin flux to volume flux in skin and muscles of intact, anesthetized rats is low, with sigma AS in the range 0.98 to greater than 0.99.
- Research Organization:
- Univ. of California, Davis (USA)
- OSTI ID:
- 7092673
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 255
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALBUMINS
MEMBRANE TRANSPORT
BLOOD FLOW
BLOOD PRESSURE
CAPILLARIES
CATTLE
INTRAVENOUS INJECTION
IODINE 125
IODINE 131
MUSCLES
RATS
REGRESSION ANALYSIS
SKIN
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
INJECTION
INTAKE
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MATHEMATICS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RODENTS
RUMINANTS
STATISTICS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques