The Quantitative Theory of Autoradiography Illustrated Through Experiments With P 32 in the Chick Embryo

Abstract

The autoradiographic technique in expts. with the chick embryo was found to be an excellent method of determining the distribution of p32 between the embryo and blastoderm. The techniques and interpretations of the results based upon some simple principles of photographic sensitometry showed that the method was capable of yielding quantitative results. An interesting point was that contact for a half-life resulted in an exposure equal to half that which would be received on an indefinitely prolonged exposure. Good autoradiographs were obtained for 24-, 48-, and 72-hr. embryos. The region of the embryo had about 3 times as much radioactive P per unit area as the blastoderm. Since the thicknesses of the 2 regions were comparable, the embryo was concentrating the available P at a fairly high rate.