title: Circadian adrenocortical periodicity changes in adult rats stimulated during early development--I. Effect of prednisolone.
abstract: The aim of this study was to test the feasibility of manipulating the adrenocortical circadian rhythm in adult rats by early postnatal prednisolone treatment. Prednisolone, when injected at 7-9 or 17-19 days after birth, produced a permanent suppression of the circadian rhythm of the basal levels of plasma 11-OH-corticosteroids and the rhythm of its responsiveness to stress. The administration of prednisolone at age of 2-4 or 12-14 days did not affect the circadian adrenocortical patterns in adults. Evidence was obtained for the existence of two critical periods during early development. Stimulation with prednisolone during these periods caused a profound modification of circadian periodicity in the performance of the pituitary-adrenocortical system. This modification was not related to changes in adrenal cortex ACTH responsiveness and also to altered stress reactivity of the pituitary-adrenocortical system. It was the presumable consequence of a blockage of a regulatory central mechanism initiating circadian variations in the pituitary-adrenocortical function. The existence of two distinct critical periods suggests that some prednisolone-sensitive links of this central pacemaker mechanism mature asynchronously during early postnatal life.
authors.affiliation: Institute of Cytology and Genetics, Siberian Department of the USSR Academy of Sciences, Novosibirsk.
authors.forename: E V
authors.initials: EV
authors.lastname: Naumenko
authors.forename: A L
authors.initials: AL
authors.lastname: Markel
authors.forename: S B
authors.initials: SB
authors.lastname: Lurie
authors.forename: E M
authors.initials: EM
authors.lastname: Kazin
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism / Q000502:physiology*; D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects*; D066298:In Vitro Techniques; D011239:Prednisolone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013312:Stress, Physiological / Q000378:metabolism
chemical_list: D000305:Adrenal Cortex Hormones; D000324:Adrenocorticotropic Hormone; D011239:Prednisolone