Determination of the role of brain norepinephrine and dopamine in the regulation of pituitary prolactin and LH during several reproductive stages are being studied. It has been determined that L-DOPA will significantly decrease prolactin in ovariectomized rats primed with estrogen and progesterone. The site of action of L-DOPA is both the hypothalamus and pituitary. Inhibition of catecholamine synthesis by injection of methyl tyrosine significantly increased prolactin but did not affect LH levels in ovariectomized and lactating rats.