The role of catecholamines in stimulating the release of pituitary ovulating hormone(s) in sheep.

Noradrenaline (NA) or dopamine (DA) were infused into the 3rd cerebral ventricle of the ewes in the stage of late anestrus and the release of LH and the induction of ovulation (IO) were followed. After the infusion of NA the release of LH and IO in the ewes with so-called "activated" ovaries was observed, while no reaction was found in the ewes with the "inactive" ovaries. The infusion of DA was without any effect either in the ewes with "activated" or with "inactive" ovaries.