[PubMed] [Google Scholar] 40. 70% of the genes showing maximum expression during the active/dark period. These genes were grouped into eight functional categories, which were examined within the context of their temporal expression. Circadian oscillations were also observed in plasma leptin, corticosterone, insulin, glucose, triglycerides, free fatty acids, and LDL cholesterol. Circadian oscillation in these physiological measurements along with the functional categorization of these genes suggests an important role for circadian rhythms in controlling various functions in white adipose tissue including adipogenesis, energy metabolism, and immune regulation. and = 3) for that time, and 24-h time series plots were constructed from these data. A nonlinear least-squares fitting of individual replicate data points was conducted with MATLAB (Mathworks, Natick, MA), which utilized a regular sinusoidal function [A sin (B + C) + mean]. In this sinusoidal model A, B, and C reflect the amplitude, period, and phase of the oscillation. Genes that could be curve fitted with and mRNA expression peaked during Celastrol the early Celastrol light period [zeitgeber time (ZT) 1]. transcription factors peaked during the early dark period (ZT 13 for and and ZT 16 for transcription factor peaked during the late dark period (ZT 21). Nuclear orphan receptors and showed similar expression patterns, with peak expression occurring at the transition from the light to the dark period (ZT 12). The clock-controlled transcription factors all showed very similar expression patterns, with peaks occurring at the early dark Celastrol period (ZT 13), while also showed circadian rhythmicity in its expression, with maximal expression occurring at the transition between the light and the dark period (ZT 12). Although the Rat 230_2 chips contained probe sets for ((((((((((and (((((((is placed in the transcription regulation category because it regulates the expression of many genes by functioning as a transcription factor, but it can also be placed in Cell Cycle/Apoptosis because of its role in regulating cellular proliferation and differentiation. In addition, Supplemental Table S3 provides the normalized data for each of these 190 probe sets. Transcription, Posttranscription, and Translation Regulation represents the most populated functional group, with 49 probe sets representing 41 genes. This functional group includes genes encoding transcription factors, activators, and repressors. The core clock and clock-controlled transcription factors are included in this functional group. Several of the transcription factors in this category play an important role in regulating adipogenesis and adipocyte differentiation. For example, and are involved in adipocyte differentiation (25, 39). Both genes are a part of and show maximal mRNA expression in the early dark/active period (ZT 14). The expression patterns of these genes along with several other examples are presented in Supplemental Fig. S1. Another example Celastrol is usually (glucocorticoid-induced leucine zipper), which acts as a negative regulator of adipogenesis by repressing the expression of (and ((((((and influences the production of insulin by beta islet cells, and modulate various aspects of insulin signaling pathways in a tissue-specific manner, thereby regulating energy homeostasis. Furthermore, also play an important role in regulating adipogenesis and adipocyte differentiation (12, 44, 46). Inflammation/Immune Response consists of nine probe sets representing seven genes that regulate and mediate immune responses both under normal and inflammatory conditions. For example, ((((14). Furthermore, two probe sets corresponding to the (is usually a low-affinity receptor for IgG Smcb molecules and is critical in regulating antibody-mediated cellular toxicity, inflammatory mediator release, phagocytosis of opsonized microbes, and antigen processing and presentation (40, 42). Cell Cycle/Apoptosis consists of 14 probe sets representing 12 different genes with functions in regulating cell proliferation, differentiation, and apoptosis. For example, cyclin-dependent kinase inhibitor 1A (CDKN1A, also called p21) is usually a negative regulator of cell cycle progression by inhibiting the activity of cyclin-Cdk2 and cyclin-CDK4 complexes in the G1-to-S phase transition (6). CDKN1A positively.