A clinician is designing a patient education handout that must concisely state hormonal actions involved in lactation. Which concise, accurate synthesis should be included to explain how both hormones interact during a typical feeding?

• A. Lactation is regulated entirely by local breast tissue autocrine signals; systemic hormones are not required, so a handout need only discuss mechanical emptying and not hormonal coordination.
• B. Oxytocin stimulates the mammary alveoli to produce antibodies while prolactin acts on the adrenal glands to mobilize maternal fat stores, and both are secreted in response to visual cues of the infant alone.
• C. Prolactin and oxytocin are released from the posterior pituitary in a fixed ratio that depends primarily on circadian rhythm rather than infant suckling, with prolactin responsible for milk ejection and oxytocin for milk synthesis.
• D. Suckling triggers hypothalamic signals that reduce inhibitory dopamine and stimulate pituitary release of prolactin to increase milk synthesis; concurrently oxytocin release causes myoepithelial cell contraction to eject milk—both processes are coordinated during feeding.

Answer: (D)