Prostaglandin Biosynthesis, Transport, and Signaling in Corpus Luteum: A Basis for Autoregulation of Luteal Function

The corpus luteum (CL) is a transient ovarian endocrine gland formed from the ovulated follicle. Progesterone is the primary secretory product of CL and is essential for establishment of pregnancy in mammals. In the cyclic female, the life span of CL is characterized by luteal development, maintenance, and regression regulated by complex interactions between luteotrophic and luteolytic mediators. It is universally accepted that prostaglandin (PG) F2a is the luteolysin whereas PGE2 is considered as a luteotropin in most mammals. New emerging concepts emphasize the autocrine and paracrine actions of luteal PGs in CL function. However, there is no report on selective biosynthesis and cellular transport of luteal PGE2 and PGF2α in the CL of any species. We have studied the expression of enzymes involved in the metabolism of PGE2 and PGF2α, cyclooxygenase (COX)-1 and -2, PGE and F synthases, PG 15-dehydrogenase, and PG transporter as well as receptors (EP2, EP3, and FP) throughout the CL life span using a bovi...