Project description:BACKGOUND: Drinking water can be contaminated with pharmaceuticals. However, it is uncertain whether this contamination can have harmful consequences for the liver, especially in the context of obesity. OBJECTIVES: To determine whether chronic, low dose exposure to pharmaceuticals could have deleterious effects in livers of lean and obese mice. METHODS: Lean and ob/ob male mice (5-week-old) were treated for 4 months with a mixture of 11 drugs (acetaminophen, caffeine, carbamazepine, cotinine, diclofenac, erythromycin, ibuprofen, phenazone, roxithromycin, salicylic acid and sulfamethoxazole) provided in drinking water at a concentration of 1 mg/L (for each drug). At the end of the treatment, investigations were performed in liver and plasma. RESULTS: Some liver and plasma abnormalities were observed in ob/ob mice treated with the cocktail containing 1 mg/L of each drug. For this dosage, a gene expression analysis by microarray showed altered expression of circadian genes (e.g. Bmal1, Dbp, Cry1) in lean and obese mice. RT-qPCR analyses carried out in all groups of animals indicated that expression of 8 different circadian genes was significantly modified in a dose-dependent manner. For some genes, a significant modification was observed for dosages as low as 100-1,000 ng/L. Drug mixture and obesity presented an additive effect on circadian gene expression. These data were confirmed in an independent study performed in female mice. CONCLUSIONS: Chronic, low dose exposure to pharmaceuticals disturbed hepatic expression of circadian genes, especially in obese mice. Because some of the 11 drugs can be found in the drinking water at such concentrations (e.g. acetaminophen, carbamazepine, ibuprofen) our data could be relevant in environmental toxicology, in particular for obese individuals exposed to these contaminants. C57BL/6J lean and ob/ob male mice (5-week-old) were treated for 4 months with a mixture of 11 drugs provided in drinking water at a concentration of 1 mg/L (for each drug). 4 groups were designed: untreated versus treated WT and ob/ob mice (n=6 mice per group).

Project description:The expression of adipogenic genes is decreased in obesity and diabetes mellitus ; Samuel T. Nadler*, Jonathan P. Stoehr*, Kathryn L. Schueler*, Gene Tanimoto, Brian S. Yandell, and Alan D. Attie*,Â§ ; Departments of * Biochemistry, and Statistics and Horticulture, University of Wisconsin, Madison, WI, 53706; and Affymetrix, Inc., Santa Clara, CA 95051 ; Communicated by Neal L. First, University of Wisconsin, Madison, WI, July 13, 2000 (received for review April 3, 2000) ; Obesity is strongly correlated with type 2 diabetes mellitus, a common disorder of glucose and lipid metabolism. Although adipocytes are critical in obesity, their role in diabetes has only recently been appreciated. We conducted studies by using DNA microarrays to identify differences in gene expression in adipose tissue from lean, obese, and obese-diabetic mice. The expression level of over 11,000 transcripts was analyzed, and 214 transcripts showed significant differences between lean and obese mice. Surprisingly, the expression of genes normally associated with adipocyte differentiation were down-regulated in obesity. Not all obese individuals will become diabetic; many remain normoglycemic despite profound obesity. Understanding the transition to obesity with concomitant diabetes will provide important clues to the pathogenesis of type 2 diabetes. Therefore, we examined the levels of gene expression in adipose tissue from five groups of obese mice with varying degrees of hyperglycemia, and we identified 88 genes whose expression strongly correlated with diabetes severity. This group included many genes that are known to be involved in signal transduction and energy metabolism as well as genes not previously examined in the context of diabetes. Our data show that a decrease in expression of genes normally involved in adipogenesis is associated with obesity, and we further identify genes important for subsequent development of type 2 diabetes mellitus. Experiment Overall Design: For obesity study, lean samples include C57BL/6J lean, (C57BL/6J X BTBR) F1 and BTBR lean, obese sampples incluse C57BL/6J-ob/ob, (C57BL/6J X BTBR) F2-ob/ob and BTBR-ob/ob. All samples are subjected to Mu11K A and B arrays. Experiment Overall Design: For diabetes study, B6-ob/ob, (C57BL/6J X BTBR) F2-ob/ob low glucose, (C57BL/6J X BTBR) F2-ob/ob medium glucose, (C57BL/6J X BTBR) F2-ob/ob high glucose, and BTBR-ob/ob samples were analyzed for genes whose expression levels changes correlated with the plasma glucose levels in these mice. All samples are subjected to Mu11K A and B arrays.

Project description:A series of two color gene expression profiles obtained using Agilent 44K expression microarrays was used to examine sex-dependent and growth hormone-dependent differences in gene expression in rat liver. This series is comprised of pools of RNA prepared from untreated male and female rat liver, hypophysectomized (‘Hypox’) male and female rat liver, and from livers of Hypox male rats treated with either a single injection of growth hormone and then killed 30, 60, or 90 min later, or from livers of Hypox male rats treated with two growth hormone injections spaced 3 or 4 hr apart and killed 30 min after the second injection. The pools were paired to generate the following 6 direct microarray comparisons: 1) untreated male liver vs. untreated female liver; 2) Hypox male liver vs. untreated male liver; 3) Hypox female liver vs. untreated female liver; 4) Hypox male liver vs. Hypox female liver; 5) Hypox male liver + 1 growth hormone injection vs. Hypox male liver; and 6) Hypox male liver + 2 growth hormone injections vs. Hypox male liver. A comparison of untreated male liver and untreated female liver liver gene expression profiles showed that of the genes that showed significant expression differences in at least one of the 6 data sets, 25% were sex-specific. Moreover, sex specificity was lost for 88% of the male-specific genes and 94% of the female-specific genes following hypophysectomy. 25-31% of the sex-specific genes whose expression is altered by hypophysectomy responded to short-term growth hormone treatment in hypox male liver. 18-19% of the sex-specific genes whose expression decreased following hypophysectomy were up-regulated after either one or two growth hormone injections. Finally, growth hormone suppressed 24-36% of the sex-specific genes whose expression was up-regulated following hypophysectomy, indicating that growth hormone acts via both positive and negative regulatory mechanisms to establish and maintain the sex specificity of liver gene expression. For full details, see V. Wauthier and D.J. Waxman, Molecular Endocrinology (2008)

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