Prolactin is primarily thought of as a hormone rather than a neurotransmitter. However, the central nervous system contains prolactin receptors and prolactin affects the levels of other hormones. Prolactin can affect certain dopamine and oxytocin functions.

Human

Absence of orgasm-induced prolactin secretion in a healthy multi-orgasmic male subject

The quality of sexual experience in women correlates with post-orgasmic prolactin surges: results from an experimental prototype study

Coitus-induced orgasm stimulates prolactin secretion in healthy subjects

Prolactin secretory rhythm in women: immediate and long-term alterations after sexual contact

The post-orgasmic prolactin increase following intercourse is greater than following masturbation and suggests greater satiety

Cardiovascular and endocrine alterations after masturbation-induced orgasm in women

Animal

Prolactin release after mating and genitosensory stimulation in females

No evidence for prolactin’s involvement in the post-ejaculatory refractory period