Tissue to plasma capillary permeability of 131I-albumin in the perfused rabbit ear.
The tissue to plasma transfer of 131I-albumin was recorded in perfused rabbit ears (n = 6) following equilibration for 24 hr. 125I-fibrinogen served as the plasma marker, and was introduced intravenously 15 min before clamping. The ears were rollerpump perfused with isotonic diluted plasma at a constant rate of (mean +/- SD) 5.1 +/- 1.5 ml (min.100 g)-1. The mean extravascular albumin distribution volume was 12.4 +/- 1.1 ml.100 g-1, and the fibrinogen volume (plasma volume in tissue) was 3.1 +/- 0.4 ml.100 g-1 as determined from biopsies of the contralateral ear. The initial transfer of albumin was marked, and occurred at rates corresponding to a unidirectional clearance (Cl(0)) of 0.068 +/- 0.012 ml (min.100 g)-1. However, with a reduction of mean interstitial albumin tracer content of no more than 4%, net transport decreased to reach slowly declining levels 5 to 10 times lower within 10 min of continued perfusion. The decrease was considered due to rapid exhaustion of a small interstitial pool of tracer immediately adjacent to the exchange vessel membrane, followed by an increasingly retarded outwash from more distant areas. The results suggest a bimodal structural resistance to albumin movement: a relatively low resistance in the capillary membrane, and a considerable restriction to albumin transport located within the interstitial space.
Bent-Hansen
L
L
Department of Medicine B, Rigshospitalet, University of Copenhagen, Denmark.
Svendsen
J H
JH
D000818:Animals; D015415:Biomarkers; D001706:Biopsy; D002199:Capillary Permeability; D002200:Capillary Resistance; D004423:Ear / Q000098:blood supply* / Q000473:pathology; D005340:Fibrinogen / Q000378:metabolism; D007457:Iodine Radioisotopes; D011817:Rabbits; D012709:Serum Albumin / Q000378:metabolism*
D015415:Biomarkers; D007457:Iodine Radioisotopes; D012709:Serum Albumin; D005340:Fibrinogen