Neuroendocrine processes in the establishment of pregnancy and pseudopregnancy in rats

Rats, like mice, hamsters and other small rodents, have a short, incomplete estrous cycle. They lack a spontaneous luteal phase, and the corpora lutea (CL) of the estrous cycle are short-lived and nonfunctional. The activation of the luteal phase in these incompletely cycling females depends on the neuroendocrine reflex provided by the male at the time of mating. In this article we review our research on the cervix-brain-pituitary-ovary interaction at the endocrine, neuroendocrine, neurotransmitter and behavioural levels, dealing with the chain of events initiated by the male and necessary for the establishment of the progestational state.