GOLD Learning Speakers

Many changes take place during pregnancy to prepare for the physical and physiological challenges of becoming a mother, including numerous adaptations in the maternal brain. Dynamic fluctuations in key hormones during pregnancy induce these adaptive changes to enable the mother’s physiology to adjust to the new demands of these reproductive states and to provide the optimal environment for the development of her baby. Evidence shows that the “lactogenic hormones” (i.e. the multiple pituitary and placental hormones that act through the prolactin receptor) are critical for many of the adaptive changes that occur during pregnancy. It is well accepted that prolactin is required for lactation, but it is now clear that these hormones have a much wider role, influencing maternal behaviour and the maintenance of lactation infertility. Surprisingly, we have shown that prolactin action in the brain also mediates metabolic changes, including stimulation of food intake, a profound suppression in voluntary physical activity in pregnancy, and there is exciting new data showing a role for prolactin in thermoregulation. Collectively, we believe these observations are consistent with the hypothesis that prolactin (and its placental homologue placental lactogen) plays a key role in coordinating the behavioural and physiological adaptations to pregnancy in the mother, and lactation could be considered simply another in this suite of prolactin-mediated physiological adaptations. These data highlight a much more comprehensive role for prolactin in the process of mammalian reproduction than is typically considered for this “lactation hormone”.