Premium
THE DIFFUSION OF [ 131 ]‐LABELLED ALBUMIN IN THE EXTRACELLULAR SPACE OF AMPHIBIAN MUSCLE
Author(s) -
Freeman Shirley E,
Freeman WP,
Dewhurst DJ
Publication year - 1966
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1966.49
Subject(s) - extracellular , albumin , diffusion , connective tissue , chemistry , biophysics , interstitial space , extracellular fluid , anatomy , biochemistry , biology , endocrinology , physics , thermodynamics , genetics
Summary A study has been made of the kinetics of diffusion of [ 131 I]‐labelled albumin in the extracellular space of the sartorius muscle of the toad. Efflux curves have been compared with theoretical curves for diffusion from a plane sheet or cylinder. Unlike both these curves, the semilogarithmic plot of efflux was found never to straighten. The loss of labelled albumin from the muscle at early times was faster than predicted from the plane sheet model. This is presumed to be due to loss from the ends of the elliptical muscle; at later times the loss was slower than predicted. An analogue computer was used to describe mathematically the delay in the late‐time diffusion of labelled albumin. The structure of the muscle and the distribution of albumin in the extracellular space were studied histologically. The labelled albumin did not enter the muscle cells. It penetrated all the connective tissue of the extracellular space, including such dense areas of connective tissue as the adventitia of blood vessels, and nerve sheaths. It did not enter the capillaries and, accordingly, it will underestimate the volume of extracellular water by an amount equal to the trapped plasma volume in the vascular bed. Staining for mucopolysaccharides, which could be expected to delay protein diffusion, was negative. The sequestration of labelled albumin is probably at least partly due to an impeded diffusion through areas such as the nerve sheath, which is known to delay the diffusion of small molecular weight substances.