Effect of actinomycin D on the structure of the chromatoid body in the rat spermatids

Cell Tissue Res. 1977 Nov 7;184(3):411-21. doi: 10.1007/BF00219900.


The effect of actinomycin D on the chromadoid body of rat spermatids has been studied by light and electron microscopy, high resolution autoradiography and biochemical methods. Actinomycin D caused structural changes in the chromatoid body of young round nucleated spermatids. The normal irregularily lobulated chromatoid body acquired a ring-like configuration 12 h after an intratesticular injection of 2 microgram of the drug. The labelling of the chromatoid body with 3H-uridine which can normally be seen after 12 h was also abolished by actinomycin D. These observations lead to the suggestion that the chromatoid body contains a store of long-lived mRNA molecules that are activated later during spermiogenesis when transcription in the spermatid nucleus has ceased but a high level of protein synthesis still persists.

MeSH terms

  • Animals
  • Autoradiography
  • Cytoplasm / drug effects
  • Dactinomycin / pharmacology*
  • Male
  • Microscopy, Electron
  • RNA, Messenger
  • Rats
  • Spermatids / drug effects*
  • Spermatids / ultrastructure
  • Spermatozoa / drug effects*
  • Time Factors
  • Transcription, Genetic


  • RNA, Messenger
  • Dactinomycin