Prolactin release is inhibited by

Dopamine serves as the major prolactin-inhibiting factor or brake on prolactin secretion. Dopamine is secreted into poal blood by hypothalamic neurons, binds to receptors on lactotrophs, and inhibits both the synthesis and secretion of prolactin. Ref: guyton and hall textbook of medical physiology 12 edition page number: 550,551,552