to determine whether brain monoaminergic neurons are involved in the release of gonadotropins responsible for estrogen increases before proestrus , various inhibitors and precursors of monoamine biosynthesis were administered subcutaneously or intracranially to the 3rd ventricle at 10.00 or 20.00 on the day before proestrus , the 2nd day of diestrus ( dii ) in 4-day cycling rats .
C0006104
brain
C0149555
3rd ventricle