Chromatoid body and haploid gene activity: Actinomycin D induced morphological alterations

New evidence about the dependence of the chromatoid body on the haploid gene activity during early spermiogenesis has been obtained in rats by morphological studies after intratesticular injection of Actinomycin D. Normally, this organelle shows an irregularly lobulated structure of dense filamentous material but following AMD administration, it appears as a ring in the electron microscopic sections, in the phase contrast microscopic and light microscopic preparations of living and sectioned material. The alterations appeared 12 h after the injection, which corresponds to the time required for the incorporation of the radioactivity to this organelle after a pulse with tritiated uridine.