Pregnant Women Who Have Begun Labor but in Whom This

Pregnant women who have begun labor but in whom this process is no longer progressing are often given an IV injection of Pitocin to stimulate uterine contractions and facilitate parturition. Pitocin is a trade name of a hormone produced in what endocrine tissue?

A) Pars distalis
B) Ovarian follicles
C) Pars nervosa
D) Placenta
E) Pars tuberalis