[Chronotolerance of corticosterone on DNA synthesis in young growing rats].
Plasma corticosterone and DNA synthesis were measured during 2 circadian periodes following the 25th day of rats. Corticosterone (5 mg/kg) injected at 05 h (1 h before the normal corticosterone bathyphase) inhibits and dissynchronizes the nycthemeral evolution of the two parameters during the two subsequent periods. The same corticosterone administration injected at 17 h (1 h before the normal corticosterone acrophase) inhibits the first DNA synthesis wave but both parameters are nycthemerally restored from the second period. In this last case, the area under the second DNA curve compensates the inhibition of the first wave. The results are discussed in the view of chronocorticotherapy recommended in patients.
Barbason
H
H
Cancérologie Expérimentale, Radiobiologie et Chronobiologie, Université de Liège, Belgique.
Laloux
I
I
Gustin
J F
JF
Milis
G
G
Kaouass
M
M
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000097:blood / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000502:physiology*; D003345:Corticosterone / Q000097:blood / Q000494:pharmacology*; D004261:DNA Replication / Q000187:drug effects*; D008940:Mitotic Index / Q000187:drug effects*; D051381:Rats
D000893:Anti-Inflammatory Agents; D003345:Corticosterone
Chronotolérance de la corticostérone sur la synthèse du DNA chez le jeune rat en croissance.