Sex-different and growth hormone-regulated expression of microRNA in rat liver

• Published in: BMC molecular biology Vol. 10; no. 1; p. 13
• Main Authors: Cheung, Louisa, Gustavsson, Carolina, Norstedt, Gunnar, Tollet-Egnell, Petra
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 23.02.2009; BioMed Central
• Subjects: Animal Nutritional Physiological Phenomena; Animals; DNA microarrays; Female; Gene expression; Gene Expression Profiling; Gene Expression Regulation - drug effects; Genetic aspects; Growth Hormone - physiology; Liver; Liver - drug effects; Liver - metabolism; Male; Medicin och hälsovetenskap; MicroRNAs - metabolism; Physiological aspects; Rats; Sex Factors; Somatotropin; Starvation - physiopathology; Sweden
• ISSN: 1471-2199; 1471-2199
• DOI: 10.1186/1471-2199-10-13

MicroRNAs (miRNAs) are short non-coding RNAs playing an important role in post-transcriptional regulation of gene expression. We have previously shown that hepatic transcript profiles are different between males and females; that some of these differences are under the regulation of growth hormone (GH); and that mild starvation diminishes some of the differences. In this study, we tested if hepatic miRNAs are regulated in a similar manner. Using microarrays, miRNA screening was performed to identify sex-dependent miRNAs in rat liver. Out of 324 unique probes on the array, 254 were expressed in the liver and eight (3% of 254) of those were found to be different between the sexes. Among the eight putative sex-different miRNAs, only one female-predominant miRNA (miR-29b) was confirmed using quantitative real-time PCR. Furthermore, 1 week of continuous GH-treatment in male rats reduced the levels of miR-451 and miR-29b, whereas mild starvation (12 hours) raised the levels of miR-451, miR-122a and miR-29b in both sexes. The biggest effects were obtained on miR-29b with GH-treatment. We conclude that hepatic miRNA levels depend on the hormonal and nutritional status of the animal and show that miR-29b is a female-predominant and GH-regulated miRNA in rat liver.