Evidence That Vitamin A Is Not Required for the Biosynthesis of Ovalbumin in Chicks

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Abstract
Four-day-old pullets fed a vitamin A-deficient diet were stimulated daily with 1 mg 17β-estradiol-3-benzoate/day for 6 to 19 days. The onset of vitamin A deficiency had no effect on oviduct growth in these chicks; even though vitamin A-deficient chicks showed a severe decline in growth rate while controls (fed the same diet supplemented with retinyl palmitate) continued to grow, estrogen stimulation resulted in similar oviduct size. Ovalbumin concentrations of estrogen-stimulated chicks were determined by immunoprecipitation of the soluble protein supernatant fraction of oviduct. The concentration of ovalbumin in oviducts of chicks fed a vitamin A-supplemented diet was similar to the concentration in oviducts of chicks fed a vitamin A-deficient diet. The incorporation of [3H]glucosamine and 14C-amino acids into immunoprecipitable ovalbumin, following the in vitro incubation of minced oviduct, indicated that ovalbumin synthesis was not affected by vitamin A deficiency. The specific activity of incorporated [3H]glucosamine, the 14C-amino acid incorporation into ovalbumin, the relative rate of ovalbumin synthesis, and the relative efficiency of [3H]glucosamine incorporation into ovalbumin were each similar between the two diet groups. The relative efficiency of [3H]glucosamine incorporation into sodium dodecyl sulfate and dithiothreitol extractable membranous proteins of oviduct was not affected by vitamin A deficiency.