Estimation of thyroxine distribution in man

J. T. Nicoloff; J. Thomas Dowling

doi:10.1172/JCI105712

^{Department of Medicine of King County Hospital, Seattle, Washington}

^{Department of Medicine of University of Washington, Seattle, Washington}

^{Veterans Administration Center, Wadsworth Hospital, and the University of California at Los Angeles, California}

Find articles by Nicoloff, J. in: JCI | PubMed | Google Scholar

^{Department of Medicine of King County Hospital, Seattle, Washington}

^{Department of Medicine of University of Washington, Seattle, Washington}

^{Veterans Administration Center, Wadsworth Hospital, and the University of California at Los Angeles, California}

Find articles by Dowling, J. in: JCI | PubMed | Google Scholar

Published in Volume 47, Issue 1 on January 1, 1968
J Clin Invest. 1968;47(1):26–37. https://doi.org/10.1172/JCI105712.
© 1968 The American Society for Clinical Investigation

Published January 1, 1968 - Version history

A group of 13 normal subjects were evaluated for their extrathyroidal thyroxine distribution. The method employed the measurement of the acute plasma disappearance of a thyroxine-¹³¹I tracer and its concomitant uptake into the liver and forearm. The analysis of these parameters allowed the theoretical construction of a four compartmental mathematical model system comprised of the plasma, extracellular fluid, hepatic, and extrahepatic thyroxine pools. The results of this analysis revealed that the exchange of thyroxine from the plasma into the hepatic and extrahepatic cellular fluid spaces appeared, in general, to be rapid, while the uptake into the extrahepatic tissues was relatively slow. The calculated distribution of thyroxine at equilibrium was estimated to be 14% in liver, 34% in extrahepatic tissues, and 26% each in the plasma and extracellular fluid pools in this group of normal subjects.