Abstract
It is well documented that the corpus luteum is required for a successful pregnancy. The primary function of the corpus luteum is to secrete progesterone, which has several biological effects on target tissues in the reproductive system to prepare them for support of pregnancy or to provide nourishment to the conceptus. In most domestic species including cattle, three organ systems regulate the function of the corpus luteum. The anterior pituitary gland secretes LH, which is the primary hormone responsible for stimulating the secretion of progesterone. The uterus has a luteolytic effect during the late luteal phase of the estrous cycle. This luteolytic effect of the uterus is mediated via secretion of prostaglandin F2α. Finally, the conceptus has either direct luteotropic or antiluteolytic effects. However, there is increasing evidence for the existence of substances in luteal tissue which are able to act locally, either alone or by modulating the action of the gonadotropins, thus modifying the functions of corpus luteum. The intra-luteal regulators consist of peptides, eicosanoids, growth factors, cytokines, and neurotransmitters. Available data suggest an important role for these substances in the control of luteal function during not only pregnancy but the estrous cycle as well.
