The objective of this experiment is to study genes and proteins differing across reproductive stages in swine. RNA from ovary, from sows on heat, 15 and 45 days of pregnancy have been hybridised in porcine oligonucleotide microchips to characterize changes in gene expression profile between different reproductive stages. Expression differences in 281 genes (posterior probability <10-11) have been found between expression at different stages in ovary. One of these genes, vinculin, showed 100 times more expression on heat than at 45 days of pregnancy, so we chose that gene for immunohistochemistry and western blot analysis. On immunohistochemistry we found that ovaries of sows on heat showed stronger vinculin staining than ovaries stroma of sows at 30 days of pregnancy. On western blot, significant differences appeared only between heat and 45 days of pregnancy.