Abstract
Summary
Charcoal premixed with dextran of average molecular weight 250,000 almost instantly adsorbs free human growth hormone or human chorionic “growth hormone-prolactin,” but rejects antibody-bound hormone. The use of such dextran-coated charcoal makes simpler and more rapid the immunoassay of these hormones in biologic fluids, using radioisotope dilution with I131-hormone and “biopsy” of the hormone pool by antibody to the hormone. The procedure yields a straight line graph when hormone added is plotted against hormone recovered.
Addendum: M. S. Wool and H. A. Se-lenkow recently published an abstract on the use of charcoal coated with Dextran 150 for assay of human growth hormone (Proc. 48th Meeting, Endocrine Society, Chicago, June 20-22, 1966, p. 123).
S. Reichlin and his associates at University of Rochester School of Medicine found excellent similarities of separation in comparison of the coated charcoal with the double antibody method for growth hormone assay. E. Knobil and his associates at University of Pittsburgh School of Medicine now have two papers in press in Endocrinology, describing studies on regulation of growth hormone secretion in the rhesus monkey using the charcoal method, which they find gives somewhat greater precision than the chromato-electrophoretic procedure and is more rapid and convenient. They have run a number of duplicate assays using both separation procedures and found that they yielded essentially identical results.
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