Postnatal Ontogeny of the Circadian Expression of the Adrenal Clock Genes and Corticosterone Rhythm in Male Rats.
The postnatal synchronization of the circadian variation of the adrenal clock genes in mammals remains unknown. We evaluated the postnatal ontogeny of daily variation of clock genes (Clock/Bmal1/Per1/Per2/Per3/Cry1/Cry2/Rorα/Rev-Erbα) and steroidogenesis-related genes (Star and Mc2r) in rat adrenals and its relationship with the emergence of plasma corticosterone rhythm using cosinor analysis. Plasma corticosterone circadian rhythm was detected from postnatal day (P)1, with morning acrophase, between zeitgeber time (ZT)0 and ZT2. From P14, there was a nocturnal acrophase of corticosterone at ZT20, which was associated with pups' eye opening. From P3 there was a circadian variation of the mRNA expression of Bmal1, Per2, Per3, and Cry1 genes with morning acrophase, whereas Rev-Erbα had nocturnal acrophase. From P14, Bmal1, Per2, Per3, and Cry1 acrophases advanced by approximately 10 hours, as compared with early neonatal days, becoming vespertine-nocturnal. In all postnatal ages, Per2 and Cry1 circadian profiles were synchronized in phase with the circadian rhythm of plasma corticosterone, whereas Bmal1 was in antiphase. An adult-like Star circadian rhythm profile was observed only from P21. In conclusion, our original data demonstrated a progressive postnatal maturation of the circadian variation of the adrenal clock genes in synchrony with the development of the corticosterone circadian rhythm in rats.
Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Silvia Liliana Ruiz
SLR
Roa
Department of Social Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Edson Zangiacomi
EZ
Martinez
Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Clarissa Silva
CS
Martins
Department of Pediatrics, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Sonir Rauber
SR
Antonini
Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Margaret
M
de Castro
Department of Internal Medicine, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP 14049-900, Brazil.
Ayrton Custódio
AC
Moreira
D000305:Adrenal Cortex Hormones / Q000235:genetics / Q000378:metabolism; D000311:Adrenal Glands / Q000254:growth & development* / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D056926:CLOCK Proteins / Q000235:genetics* / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D003345:Corticosterone / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar
D000305:Adrenal Cortex Hormones; D056926:CLOCK Proteins; D003345:Corticosterone