Final answer:
PIH is another name for prolactin-inhibiting hormone (dopamine) which is released from neurons in the hypothalamus to inhibit the secretion of prolactin, a hormone that stimulates milk production. During pregnancy, prolactin levels rise in response to prolactin-releasing hormone (PRH) from the hypothalamus.
Step-by-step explanation:
PIH stands for prolactin-inhibiting hormone. It is another name for dopamine, which is a neurotransmitter in the brain. Dopamine is released from neurons in the hypothalamus and inhibits the secretion of prolactin, a hormone produced by the anterior pituitary that stimulates milk production. During pregnancy, prolactin levels rise in response to prolactin-releasing hormone (PRH) from the hypothalamus.