Action of rat submaxillary gland extracts on neural tube growth in organ culture

Abstract

ABSTRACT Organ cultures of portions of chick embryo neural tube together with surrounding tissues, were made in order to test the action of other tissues in nearby culture, and of organ extracts added to the medium. Expiants four somites long, dissected from embryos at Stages 11 to 13 (Hamburger & Hamilton), developed and differentiated normally in vitro. Pieces of limb bud from older embryos, added to the expiants, fused with them and differentiated as usual. The addition of the limb bud pieces did not influence the size of the cultured neural tube. The addition of submaxillary gland extract to the medium produced during the first 6 hours of culture a dorsal opening of the neural tubes and, thereafter, an exuberant and irregular growth of them. Other organ extracts, purified ‘nerve growth factor’ and iodine treated submaxillary gland extract failed to produce the same action. The presence in submaxillary extracts of an active factor independent of ‘nerve growth factor’ and protease activity is deduced from our results.