A TRACER AMINO ACID AS AN INDICATOR OF NITROGEN METABOLISM.
Progress rept. no. 1, 1 Oct 62-31 Dec 62,
ALBERT EINSTEIN MEDICAL CENTER PHILADELPHIA PA
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The experiments reported are aimed at devising a simpler method of monitoring metabolism. Previous studies with seven different anabolic steroids on the uptake of the non-metabolizable amino acid, alpha-aminoisobutyric acid-1-C-14 AIB, by the levator ani muscle of the rat have shown this to be an excellent indicator of anabolism. The levator ani uptake test was shortened from 39 to 25 hours without loss of sensitivity or reproducibility. Study of quantitative relationship between AIB uptake and glycine incorporation into various tissues suggests a fixed proportionality between the two. The experiment, however, was not entirely satisfactory technically and is to be repeated. The time course study of the distribution of AIB in normal and steroid stimulated rats indicates that the maximum general anabolic effect of the four steroids tested does not occur until 96 hours. The magnitude of uptake increase by the viscera and general skeletal muscle at 96 hours, 50 to 60, indicates that these changes would be useful indicators of pure anabolism as distinct from the mixed anabolic and androgenic effect of the levator ani and other sexual tissues. Author