SEX DIFFERENCES IN LIVER GENE EXPRESSION IN WT AND SF-1 KNOCKOUT MICE

Liver development and function are dependent on specific gene expression profile. Many genes in the liver are differentially expressed between females and males and these sex differences are thought to be at least partially influenced by sex specific patterns of growth hormone secretion. The aim of this study was to examine whether sex chromosomes contribute to sex differences in the liver gene expression. Expression of Cyp4a10, Cyp2u1, Cux2and Hsd3b5, which are known to be differentially expressed between sexes in adulthood, were studied in WT and SF-1 knockout mice. Steroidogenic factor 1 knockout (SF-1 KO) mice that are born without gonads were used to determine whether there are any sex differences in the gene expression even in the absence of exposure to sex steroid hormones. Gonadectomised mice were also compared to gonadally intact mice and gene expression of studied genes was examined during estrous cycle in gonadally intact female mice. Higher expression of Cux2 and Cyp4a10 was detected in gonadally intact WT females in comparison to gonadally intact WT males and higher expression of Cyp2u1 and Hsd3b5 was detected in gonadally intact WT males in comparison to gonadally intact WT females. There were no sex differences in the expression of studied genes between WT gonadectomised and SF-1 KO mice. The results of our study therefore suggest that sex differences in the liver gene expression of the four studied genes are solely dependent on sex hormones and are not influenced by sex chromosome complement.