Project description:Effect of continuous GH treatment on old rat liver. Male rats, 2-year-old, were treated with vehicle or human GH (0.34 microgram/gram body weight) for 3 weeks. Keywords: response of old rat liver to growth hormone
Project description:Effect of continuous GH treatment on old rat liver. Male rats, 2-year-old, were treated with vehicle or human GH (0.34 microgram/gram body weight) for 3 weeks. Comparison of treated and untreated rats. Individual RNA were used for 4 microarray hybridization. Dye swapped.
Project description:A series of dual-channel gene expression profiles obtained using MWG Rat 5K microarrays (~5535 unique rat genes) and MWG Rat Liver microarrays (~1353 unique rat genes with 999 of these genes also represented on the Rat 5K microarray) was used to examine the sex-dependent and GH-dependent differences in gene expression in adult rat liver. This series is comprised of 8 randomly chosen pairings of independent male and female rat liver cDNA samples and 8 randomly chosen pairings of independent male and continuous GH-treated male rat liver cDNA samples, totaling 16 samples. Half of the samples were hybridized to the MWG Rat 5K microarrays and the other half were hybridized to the MWG Rat Liver microarrays. Comparison of the set of sex-dependent genes with the set of GH-responsive genes shows that 90% of male-dominant genes are suppressed in male rats treated with a female pattern of GH. Approximately 73% of female-dominant genes were up-regulated in the continuous GH-treated male rats. Keywords = Growth hormone Keywords = liver sexual dimorphism Keywords = cytochrome P450 Keywords = liver gene expression Keywords = dual channel cDNA microarray Keywords: repeat sample
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)