SummaryA high-performance liquid chromatographic (HPLC) meth od for simultaneous determination of 7-dehydrocholesterol (7-DHC), vitamin D3 and 25-hydroxyvitamin D3 (25-OH-D3) in tissues of fishes was established, and using this method the tissue distribution of the sterols in lamprey (Entosphenus japonicus), great blue shark (Prionace glauca), skipjack (Katsuwonus pelamis) and albacore (Thunnus alalunga) was in vestigated. The results are summarized in the following: 1) Although the alimentary canal, gall bladder and roe of lamprey and the alimentary canal of great blue shark contained comparatively high levels of 7-DHC (higher than 2,000ng/wet tissue g), the other tissues of lamprey and great blue shark and all tissues of skipjack and albacore contained only low levels of 7-DHC (lower than 1,000ng/g). There was no significant correlation between the levels of 7-DHC and vitamin D3 . 2) The contents of 7-DHC in the skin of skipjack and albacore were only 1/1 ,000 of those in the skin of rats. 3) Although the contents of vitamin D3 in the liver of skipjack and albacore were extremely high (41, 240 and 21 ,000ng/g, respectively), those in the skin were very low (454 and 257ng/g , re spectively). 4) 25-OH-D3 was detected in the viscera of skipjack , but the levels were not very high (lower than 150ng/g) . These levels were not significantly correlated with those of vitamin D3. The results suggest that large quantities of vitamin D3 in the liver of Abbreviations:7-DHC, 7-dehydrocholesterol; 25-OH-D3, 25-hydroxyvitamin D3;HPLC, high-performance liquid chromatography; M, mean; SD, standard deviation; nd, not detected.13

A commercial preparation was purified by removing peroxides and dried over anhydrous sodium sulfate, followed by distillation. The main distillate was dried again with the same drying agent. 4. Chloroform A commercial preparation was washed with concentrated H2SO4, and then with water and KOH solution. After washing again with water, it was distilled. The main distillate was dried over potassium carbonate overnight. 215 216 HIGASHI, YAMAKAWA, KINUMAKI, SUGII AND IWASAKI 1961 5. Antimony Trichloride An extra pure grade preparation of Yotsuhata Kagaku Co. was recrystal lized from the purified CHCl3.6. Acetyl Chloride An extra pure grade preparation of Kanto Kagaku Co. was used. FIG. 1 Instruments Used for Chromato graphy 7. SbCl3-Acetyl Chloride Reagent

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The preparation of vitamin A concentrate by molecular distillation was tested on some whale liver oils. The yield of each distillates and its vitamin A potency were tabulated in Tab. 1-6 and the absorption curves of each fraction were shown in Fig. 1-9. The potency of vitamnin A was corrected according to Oser's method. In the experiments, the following results were noticable.