The Effects of Vitamins on Phosphorus Metabolism in the Chick Embryo: 1. Vitamin D and the Utilization of Inorganic Phosphorus

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Abstract
Chick eggs were inj. with 0.1 ml. of isotonic NaH2PO4 with an activity of 639.5-counts/sec, or 0.12 microcuries. A part of the eggs also received 0.1 ml. of propylene glycol with 20 units of vit D; another portion, 0.1 ml. of propylene glycol only; and the last group, only NaH2PO4. The eggs were sealed with sterile paraffin, and incubated. The viable embryos were cleaned of membranes and dropped into liquid air. They were ground in a chilled mortar and the powder extracted with cold 10% trichloroacetic acid and then with 5% acid. The extract was filtered into cold, concentrated NaOH. The soln. was divided into 3 parts. The avg. acid-soluble P compds. was detd. on one part. The 2d part was pptd. with 25% Ba acetate, the ppt. was washed with Ba acetate, cen-trifuged, and a part dissolved in HNO3. The soln. was treated with ammonium molybdate reagent. This ppt. was inorganic P. The remainder of the ppt. was ashed and the P detd. This consisted of inorg. P plus adenosine P. The 3d part was hydrolyzed with normal HC1 and 0.1 normal ammonium molybdate. The P in the resulting ppt. consisted of inorganic P plus phosphocreatine. The residue from the extractions was treated with alcohol-ether. The filtrate contained phosphatide P, and the residue gave residual P containing chiefly nucleoprotein P. The group of 6 embryos receiving the P32 and vit. D showed a higher specific activity for all fractions except inorganic P and the avg. acid-soluble P than the group of 5 embryos which received P32 and propylene glycol and the 2 embryos which received only P32. The values support the view that vit. D accelerates the over-all metabolism of inorganic P in the chick embryo.

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