The levels of NE were substantially increased in all these tissues of all groups over those of untreated animals by the monoamine oxidase inhibitor and decreased to near zero by reserpine. The most significant changes in content and concentration of NE occurred in the distal isthmus, and to a lesser degree in the proximal isthmus. There was some indication of retarded egg transport associated with decreased NE in the isthmus of the reserpine-treated groups and accelerated transport with elevated NE in the isthmus of iproniazid-treated groups. These alterations in the speed of egg transport were, however, only marginal when compared to the effects of progesterone (accelerated) and estrogen treatment (retarded transport) in previous experiments. Furthermore, these hormonal treatments had both significantly elevated NE levels in the isthmus (Bodkhe and Harper, 1971).

In the present experiments total NE in the tissue was measured, and no information on changes of NE free in the neurons was obtained. Thus egg transport through the oviduct may be controlled mainly by small changes in free NE or hormones may exert their effects in ways other than by changes in noradrenergic activity.