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)
Project description:Analysis of the role of miR-21 in liver regeneration after partial hepatectomy (PHx) in chronic ethanol-treated rats through in vivo inhibition using LNAs
Project description:In this study, we analyzed the role of miR-21 in liver regeneration after partial hepatectomy (PHx) in chronic ethanol-treated rats. Male Sprague-Dawley rats were fed a liquid diet containing 36% of total calories derived from ethanol for 5 weeks; corresponding pair-fed calorie-matched controls were fed diets in which ethanol calories were replaced by carbohydrate. After 5 weeks, locked nucleic acid (LNA)-modified oligo antisense to miR-21 (AM21, Exiqon, Vedbaek, Denmark) was used to inhibit miRNA in vivo, and rats were subjected to 70% PHx. Liver samples were collected at 24h after the surgery. The excised liver samples at t=0 served as within-animal controls. Rat Gene 2.0 ST (Affymetrix, Santa Clara, CA) arrays were used to obtain global gene expression data from pooled liver samples (pools of 3 or 4 biological replicates/array, total 8 arrays). Gene expression was profiled in AM21 treated or untreated chronic ethanol-fed (EtOH) and carbohydrate control pair-fed (CHO) rat liver prior to (control, t=0) and 24 h after 70% partial hepatectomy (PHx).