ISSN:
1432-1912
Keywords:
Cyclophosphamide
;
Embryonic Development
;
DNA-Dependent RNA Polymerases
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary On day 13+0 h of gestation rats received 10 mg/kg cyclophosphamide i.p. 3, 9, and 24 h after administration of the drug the activities of the DNA-dependent RNA polymerase reactions were measured in the whole embryo and in parts of it (head, upper and lower extremities and trunk). The activities of these enzymes were correlated with the increase in the RNA content of these tissues. A relationship was established light and electron microscopically between the biochemical results and the specific alterations which occur in different structures of the embryonic tissue. The results of these investigations show that: 1. cyclophosphamide leads-in dependency on the time-to a decrease or increase in the Mn++- and/or Mg++-stimulated RNA polymerase reactions in isolated cell nuclei of individual parts of the embryo 2. alterations in the enzyme activities of individual parts of the embryo are not detected when the enzyme activity of the whole embryo is measured at the early day 13 of gestation 3. towards the end of gestation malformations can be demonstrated only in those parts of the embryo, where 24 h after the administration of cyclophosphamide the enzyme pattern shows a highly significant deviation from that of the controls and where cell necroses can be demonstrated light and electron microscopically. Moreover, in the nucleolus of the neuroepithelium segregation of its components takes place which correlates well with the decreased r-RNA polymerase activity. In this paper a disturbance of the transcription mechanisms is discussed as being the primary mode of action of cyclophosphamide in cell metabolism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00498786
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