Luteolysis (also known as
luteal regression) is the structural and functional degradation of the
corpus luteum (CL), which occurs at the end of the
luteal phase of both the
estrous and
menstrual cycles in the absence of
pregnancy. In domestic animals, luteolysis is initiated by the hormones
prostaglandin F2alpha and
oxytocin. In sheep, communication between the pars nervosa (posterior lobe of the pituitary gland), corpus luteum, and the uterus
endometrium via the circulatory system is required for luteolysis. Studies with sheep have found that, if the uterine horn ipsalateral to the ovary possessing the CL is surgically removed, the lifespan of the corpus luteum will increase drastically.