COX1 is constitutively expressed in theca cells but absent in granulosa cells, whereas COX2 is inducible by luteinizing hormone (LH)/human chorionic gonadotropin (hCG) only in granulosa cells.27 COX2 expression levels in ovaries of PCOS rats were elevated at both the gene and protein level in our research, and a synchronous increase in the levels of several PGs was also observed. This evidence concerns the gene PLOD1 and polycystic ovary syndrome.