How does the hypothalamus give orders to the pituitary? · Grey Matter

It uses two channels, one for each half of the gland.

How does the hypothalamus give orders to the pituitary?

It uses two channels, one for each half of the gland. For the anterior pituitary, hypothalamic neurons release releasing and inhibiting hormones (CRH, TRH, GnRH, GHRH, somatostatin, dopamine) into a small portal system of blood vessels that carries them straight down the stalk, and the pituitary cells answer with their own hormones. For the posterior pituitary there is no messenger at all: the gland is made of the axon endings of hypothalamic neurons, which release oxytocin and vasopressin directly into the blood when those neurons fire.