title: Effects of adrenalectomy on daily gene expression rhythms in the rat suprachiasmatic and paraventricular hypothalamic nuclei and in white adipose tissue.
abstract: It is assumed that in mammals the circadian rhythms of peripheral clocks are synchronized to the environment via neural, humoral and/or behavioral outputs of the central pacemaker in the suprachiasmatic nucleus of the hypothalamus (SCN). With regard to the humoral outputs, the daily rhythm of the adrenal hormone corticosterone is considered as an important candidate. To examine whether adrenal hormones are necessary for the maintenance of daily rhythms in gene expression in white adipose tissue (WAT), we used RT-PCR to check rhythmic as well as 24 h mean gene expression in WAT from adrenalectomized (ADX) and sham-operated rats. In addition, we investigated the effect of adrenalectomy on gene expression in the hypothalamic SCN and paraventricular nucleus (PVN). Adrenalectomy hardly affected daily rhythms of clock gene expression in WAT. On the other hand, >80% of the rhythmic metabolic/adipokine genes in WAT lost their daily rhythmicity in ADX rats. Likewise, in the hypothalamus adrenalectomy had no major effects on daily rhythms in gene expression, but it did change the expression level of some of the neuropeptide genes. Together, these data indicate that adrenal hormones are important for the maintenance of daily rhythms in metabolic/adipokine gene expression in WAT, without playing a major role in clock gene expression in either WAT or hypothalamus.
authors.affiliation: Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience , Amsterdam , The Netherlands and.
authors.forename: Yan
authors.initials: Y
authors.lastname: Su
authors.forename: Rianne
authors.initials: R
authors.lastname: van der Spek
authors.forename: Ewout
authors.initials: E
authors.lastname: Foppen
authors.forename: Joan
authors.initials: J
authors.lastname: Kwakkel
authors.forename: Eric
authors.initials: E
authors.lastname: Fliers
authors.forename: Andries
authors.initials: A
authors.lastname: Kalsbeek
mesh_terms: D054392:Adipokines / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism*; D000315:Adrenalectomy; D000818:Animals; D001683:Biological Clocks / Q000235:genetics*; D001835:Body Weight; D001921:Brain / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics; D018076:DNA, Complementary / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013997:Time Factors
chemical_list: D054392:Adipokines; D018076:DNA, Complementary; D012333:RNA, Messenger
keywords: Adrenal hormones; SCN; WAT; circadian; clock genes PVN