Posterior pituitary:

AKA neurohypophysis; one of the two lobes of the pituitary gland, the posterior pituitary secretes hormones synthesized by the hypothalamus. Specifically, the hypothalamus synthesizes the hormones oxytocin and vasopressin, then sends them to the posterior pituitary for release into the bloodstream.

Learn more:

Know your brain: Pituitary gland

Know your brain: Hypothalamus

2-Minute Neuroscience: Hypothalamus & Pituitary Gland