Recherches sur la nature d'un facteur inhibiteur de la croissance des os longs dans la race de poule Creeper

Abstract

1. 1. The cartilaginous rudiments of the tibiotarsus from Creeper and normal chick embryo siblings of 6 1 2 to 7 1 2 days were cultured in vitro, according to the organ culture technique of Wolff and Haffen, on media containing either normal or Creeper embryo extract prepared from 9- to 10-day embryos. 2. 2. The behavior of the bone rudiments in vitro varied with their developmental stage at the time of explantation: 2.1. a. The 7- to 7 1 2 - day rudiments continued their growth and their morphogenesis according to their genotype on both media. Even though the growth rate on the “Creeper” medium was consistently inferior to the rate obtained on the “normal” medium, their difference was not statistically significant. 2.2. b. The 6- to 6 1 2 - day rudiments responded differently to the two types of medium: the Creeper embryo extract permitted significantly less growth than the normal embryo extract; conversely, the “normal” extract enhanced the growth of the Creeper tibiotarsi. 3. 3. The composition of the culture media had no effect on the morphogenetic differentiation of the rudiments. Both normal and Creeper rudiments differentiated according to their genetic origin, irrespective of the nature of the embryo extract in the medium. 4. 4. The “Creeper” growth-restricting factor is not localized in the long bones; it has also been detected in the viscera of Creeper embryos, that is, in organs which are not apparently affected by the mutation.