258 IODINE 



(I-lo). The thyroid uptake was followed by external counting, and the 

 serum was analyzed for protein-bound iodine, protein-bound l^^\ and 

 inorganic P^'. The chemical determinations were according to standard 

 procedures, and the P^' was precipitated with carrier KI as silver iodide 

 for counting. The metabolism of iodine in the shark was studied by 

 intraperitoneal injection of 20 to 50 /xc into specimens of 141 to 1045 g 

 (1-16). A portion of the thyroid was wet-ashed in 5 per cent KOH for 

 counting, another portion was fixed in Bouin's fluid, and the rest was held 

 frozen for chemical analysis. Histological sections of the fixed tissue 

 were exposed on no-screen X-ray film, and the sections stained afterward 

 for histological observations. The frozen tissue was extracted overnight 

 at 10°C with normal saline, the filtered extract hydrolyzed with trypsin, 

 and the hydrolysate extracted with butyl alcohol for filter-paper chroma- 

 tography using butanol-acetic acid or butanol ammonia as solvents. 

 Frogs were given 10 mc P^^ by injection into the ventral lymph sac via the 

 thigh (1-17). The thyroids were wet-ashed in 1 ml of hot 2 A^ KOH. A 

 disk of lens paper was placed on a copper planchet and wetted with 

 a drop of 2 A" KOH. A 0.1-ml aliciuot of the ash solution was added 

 immediately, and the planchet placed on a rotating turntable under 

 an infrared lamp. Samples of gland were fixed in Bouin's fluid for 12 hr, 

 washed in 70 per cent alcohol, dehydrated, and embedded in paraffin, 

 and 10-M sections were mounted on dental X-ray film for preparation of 

 autoradiograms. 



The absorption and disposition of neutral fat in man were studied by 

 oral administration of 100 ^c P^^ in P^ '-labeled commercial olive oil 

 (1-18). The thyroid uptake was followed by external counting at 35 cm 

 from the neck with a directionally shielded gamma tube; 1-ml aliquots of 

 urine in glass vials were also gamma-counted. Serum was measured by 

 pipetting 0.2-ml aliquots onto copper planchets covered with thin absorb- 

 ent paper, and self-absorption was corrected for by use of standards pre- 

 pared with identical amounts of nonradioactive serum. The serum was 

 also treated with zinc sulfate to precipitate the proteins and lipids and 

 allow estimation of inorganic P^S also lipid P^' by difference. 



Some commercially available P^Mabeled compounds are listed as fol- 

 lows (1-19) : 



Alkyl iodidos-P" 3,5-Diiodosalicylic acid-P^i 



Casein-P^' Diiodotyrosine-P^i 

 2,4-Dichloro-5-iodophf'noxyacetic acid-Ji^i Diodrast-P'' 



(esters, salts, and amides) lodinated globulins and alhumin-P^^ 



3,5-Diiodo-4-aminobenzoic acid-P'" lodinated human serum albumin-P'i 



3,5-Diiodoanthranilic aeid-P^' lodinated oils and emulsions-P^^ 



2,5-Diidobenzoic acid-P^' 3-Iodo-4-aminobenzoic aeid-P^i 



3,4-Diiodobenzoic acid-P^i 5-Iodoanthranilic acid-P^i 



Diiodofluorescein-p2i lodobcnzcne-P^' 



