In vitro effect of orexin A on the transcriptomic profile of the endometrium during early pregnancy in pigs.

Orexin A belongs to the group of hypothalamic-derived peptides that are involved in a number of processes, such as regulation of energy metabolism, control of food intake and regulation of the reproductive system, by influencing the hypothalamic-pituitary-ovarian axis. Orexin A is also present in the endometrium, myometrium and placenta, which indicates that it may function as an important local regulator of the reproductive functions. The aim of this study was to explore the effects of orexin A on global gene expression in the endometrium of pigs during early gestation, on days 15 to 16 of pregnancy (implantation period). Orexin A altered the expression of 1,242 genes. In this group, 1,104 genes had a fold change greater than 1.2 (P < 0.05). In the group of genes with a fold change that was greater than 1.2, the expression of 457 genes were increased and 647 decreased because of the effects of orexin A. An analysis of the interactions between differentially expressed genes demonstrated that orexin A interacts with genes that potentially encode intracellular signalling pathways and factors regulating reproductive functions in the endometrium. The data from the present study indicate that orexin A affects a number of genes and processes in the endometrium of pregnant pigs and may be regarded as an important regulator of implantation, depending on maternal nutritional status.