Oxytocin
It has been shown that oxytocin differentially affects males and females. Females who are administered oxytocin are overall faster in responding to socially relevant stimuli than males who received oxytocin. Additionally, after the administration of oxytocin, females show increased amygdala activity in response to threatening scenes; however, males do not show increased amygdala activation. This phenomenon can be explained by looking at the role of gonadal hormones, specifically estrogen, which modulate the enhanced threat processing seen in females. Estrogen has been shown to stimulate the release of oxytocin from the hypothalamus and promote receptor binding in the amygdala.
Castles Made of Sand (novel)
Halfway through "Bold as Love" the two male leads agree that one day they will take oxytocin together — the intimacy drug, based on the hormone released to create the bond between mother and baby, or between monogamous reproductive partners. At the opening of the second episode we meet Ax and Sage loved-up, making out on Brighton Beach on an oxytocin high: a shocking development for readers lulled by the sexual conformity of the first volume. Ensuing chapters are devoted to the painful birth-pangs of a passionate rock and roll sexual threesome.