In the mother, suckling leads to which of the following responses?

The normal sequence of events triggered by suckling is as follows: through a response of the central nervous system, dopamine is decreased in the hypothalamus. Dopamine suppression decreases production of prolactin-inhibiting factor (PIF), which normally travels through a portal system to the pituitary gland; because PIF production is decreased, production of prolactin by the pituitary is increased. At this time, the pituitary also releases oxytocin, which causes milk to be expressed from the alveoli into the lactiferous ducts. Suckling suppresses the production of luteinizing hormone-releasing factor and, as a result, acts as a mild contraceptive (because the midcycle surge of luteinizing hormone does not occur).