Projection of fibers immunoreactive to an antiserum against gonadoliberin (LHRH) into the pineal stalk of the white-crowned sparrow,Zonotrichia leucophrys gambelii

Summary We have demonstrated a bundle of fibers, immunoreactive to an antiserum against gonadoliberin (luteinizing hormone-releasing hormone), that projects into the pineal stalk of photostimulated male Z. l. gambelii, a photoperiodic passerine species. These fibers have their origin in the dorsal division of the column of gonadoliberin-positive perikarya that extends caudodorsally from the ventromedial preoptic area to the level of the anterior commissure. After entering the habenula these fibers can be traced into the pineal stalk. This bundle is of interest because it apparently has not previously been reported in birds, and further, because the pineal body of this species is not known to have a role in the photoperiodic induction of increased rates of release of gonadotropins. Relationships of this bundle to other components of the gonadoliberin system are described briefly.