Endocrine Abstracts

The corpus luteum (CL) is a dynamic but transient endocrine gland. Although proliferation of hormone-producing cells ceases after ovulation, proliferation of endothelial cells is intense and the CL becomes highly vascularised. However, unless the CL is rescued by pregnancy, all these cells will die. Investigation of cell death in the CL offers an opportunity to study the mechanisms underlying regulated death of parenchymal and endothelial cells. Apoptosis is extensive in the CL of many sub-primate species. In contrast, in the primate, luteolysis is more difficult to analyse because it is restricted to a short, but unpredictable, time-frame; remaining parenchymal cells undergo a gradual process of involution and autophagocytosis, while dying endothelial cells may be shed rapidly into the circulation. Numerous factors have been implicated in triggering luteolysis, but determining the extent of their physiological role is a major challenge. In order to address this, we have developed a model in which factors thought to be involved may be systematically inhibited by specific antagonists administered in vivo at selected stages of the luteal phase in the marmoset monkey. The approach condenses the period of cell death in the CL to allow the sequence of molecular events to be investigated and is being employed to identify key interactions between the hormone-producing and endothelial cells that govern their survival or death.