Leptin Contributes to the Development of the Corpus Luteum.

The mechanistic events of female infertility have been investigated for over 50 years and despite progress many causes of infertility remain elusive. However, over half of idiopathic infertility issues have been attributed to a defective ovarian tissue responsible for the maintenance of a conceptus, the corpus luteum (CL). Many CL defects are attributed, in part, to abnormal vascularization (angiogenesis), which occurs primarily during the developmental stage of the luteal lifespan. A few well-established angiogenic growth promotants have been implicated in luteal angiogenic processes but the mechanisms of the process are still under investigation. Recent evidence supports a role for the adipokine hormone leptin as a probable component in the angiogenic and developmental processes of a CL. Leptin expression is present during the developmental and maturation stages of the luteal lifespan and stimulates the expression of angiogenic hormones in the CL. Induced leptin deficient CL have a higher occurrence of abnormal, underdeveloped gross morphology and an increase in the number of large diameter vessels and large luteal cells. Leptin replacement therapy in leptin deficient CL accelerates tissue development, increasing overall tissue mass and forming a structure that resembled a mature CL during the early stages of development. Collectively, the evidence supports the supposition that leptin is involved in the angiogenic and developmental processes of luteal tissue.