Gestation Regulates Growth Hormone and Its Receptor Expression in Sheep Immune Organs

There are multiple adaptations in maternal physiology, hormones, and immunology during pregnancy. Growth hormone (GH) is not only produced by the pituitary but also secreted by extra-pituitary tissues. In this study, 24 ewes were randomly divided into four groups and mated with either adult intact rams (pregnant ewes) or a vasectomized ram (nonpregnant ewes), and maternal thymus, lymph node, spleen, and liver were harvested at day 16 of nongestation and at days 13, 16, and 25 of gestation. The specified primers for GH and GH receptor (GHR) were utilized to analyze mRNA expression of GH and GHR using quantitative real-time PCR. Specified anti-GH1 antibody and anti-GHR antibody were used to detect protein expression of GH and GHR using Western blot and immunohistochemical analysis. The results revealed that there were increases in GH and GHR in the maternal spleen, GH in the liver, and GHR in the thymus and lymph nodes, but a downregulation of GH in lymph nodes during early gestation. In addition, early gestation affected GH expression in the thymus and GHR in the liver. In conclusion, it is reported for the first time that early gestation modulates GH and GHR expression in these maternal organs in a tissue-specific manner, which may regulate the function of these immune organs in ewes.