Thyroxine is bound to a serum protein which appears in the electrophoretogram just ahead of alpha-2 globulin (1-4). Triiodothyronine also associates with this thyroxine binding globulin (T.B.G.) but can be displaced readily with thyroxine -while triiodothyronine will not readily displace thyroxine. Deiss, Albright, and Larson (5) suggested that the firm binding of thyroxine to T.B.G. might account for the slower rate of disappearance of thyroxine from the plasma as compared to triiodothyronine.The purpose of this paper is to report studies on the in vitro uptake or binding by human red cells of radioactive I-131 labeled sodium iodide, human serum albumin; triiodothyronine, and thyroxine. We propose to show that the binding of L-thyroxine by plasma is one of the limiting factors in the uptake or binding of this substance by the human red cell. The uptake or binding of L-triiodothyronine is limited to a lesser degree by plasma binding and is consistently greater than the uptake or binding of L-thyroxine. mixed well, and incubated in a water bath at 37°C for an arbitrary period of 30 minutes. The tubes were then centrifuged, supernatant removed, the cells were washed and recentrifuged three times. The supernatant removed and the radioactivity remaining with the red cells was determined and was expressed as a percentage uptake of the original radioactivity. The same procedure was repeated using red blood cells which had been washed three times with normal saline before adding them to the radioactive solutions. (These will be referred to as washed cells.) MATERIALS AND METHODS BloodRadioactive (I-131) labeled sodium iodide, L-thyroxine, and L-triiodothyronine were dissolved in human plasma (obtained from the Blood Bank) and the same procedure described for the saline solution was carried out using both "washed" and "unwashed" red blood cells.Two milliliters of plasma were incubated in a H20 bath at 37°C for 30 minutes with 0.1 milliliter of an alkaline solution of stable L-thyroxine containing 4.5 micrograms per milliliter. Varying amounts of this plasma (.02 ml to 0.5 ml) were added to tubes containing 2 milliliters of radioactive (I-131) labeled L-thyroxine in normal saline (previously counted) and 2 milliliters of "washed" red cells were added immediately, mixed gently, and incubated in a water bath at 37°C for 30 minutes. At the end of 30 minutes the tubes were centrifuged, the supernatant removed, and the cells washed three times with normal saline. The amount of radioactivity remaining with the red cells was determined and expressed as described previously. The same procedure was repeated using radioactive L-triiodothyronine instead of radioactive L-thyroxine.Two milliliters of unwashed red cells were incubated at 37°C for 30 minutes with 50, 100, and 150 micrograms of stable L-thyroxine dissolved in 0.1 ml. of .02 N sodium hydroxide. The above mixture was then incubated with radioactive I-131 labeled L-thyroxine for 30 minutes at 37°C. The amount of radioactivity remaining with the red cells was determined and...

Treating pentaerythrityl tetrachloride with excess hot, highly compressed ammonia yields the tetramine C(CH2NH2)4 in 57% yield at 52% conversion; unconverted starting material is easily recovered for recycling. The ammonolysis may be conducted either in supercritical ammonia alone or in methanol as the solvent. The product amine is isolated by precipitating it as the water-insoluble disulfate; simply washing the precipitate with water yields disulfate of high purity.

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