Summary
An examination was made of the effect of treatment with methylating agents of varying carcinogenic potency and with stress inducing hormones upon DNA synthesis in the resting liver of the rat. With the methylating agents an early stimulation of DNA synthesis was observed, but this was depressed below the control levels at later times and with higher doses; hormone administration also resulted in a depression of DNA synthesis but, without any initial stimulation at the dosage employed.
Under conditions of induced stress it was found that the extent of reaction of N-methylN-nitrosourea with cellular macromolecules was enhanced. This appeared to be a general effect upon the liver cell since both DNA and rRNA were affected in a similar manner.
Zusammenfassung
In der normalen Rattenleber wurde vergleichend die DNS-Synthese nach Verabfolgung verschiedener methylierender Stoffe unterschiedlicher Carcinogenität im Zusammen wirken mit Streß-Hormonen untersucht. Durch die Methylantien wurde die DNS-Synthese zunächst stimuliert, sie fiel jedoch später und bei hohen Dosen unter die Kontrollwerte ab. Hormongabe allein führte bei der angewandten Dosierung nur zu einer Senkung der DNS-Synthese ohne vorangehende Stimulierung.
Wenn Streß induziert wurde, war die Gesamtreaktivität von N-Methyl-N-Nitrosoharnstoff mit Makromolekülen der Zelle erhöht. Dies schien allgemein für Leberzellen zuzutreffen, weil DNS und RNS gleichermaßen beeinflußt wurden.
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Magin, M.N., O'Connor, P.J., Craig, A.W. et al. The effect of hormone induced stress upon the extent of alkylation of rat liver nucleic acids by N-methyl-N-nitrosourea. Z. Krebsforsch. 84, 217–222 (1975). https://doi.org/10.1007/BF00312243
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DOI: https://doi.org/10.1007/BF00312243