Atrial gland induction of the egg-laying response inAplysia californica

Summary The atrial gland of the large hermaphroditic duct of the reproductive tract ofAplysia californica contains a substance that will cause egg laying when injected into sexually mature recipient animals. Preliminary chemical characterization of the atrial gland factor indicates that it is quite similar to the egg-laying hormone synthesized and secreted by the bag cell neuroendocrine organs of the central nervous system. In view of the apparent identity of its effects with those of the egg-laying hormone on presumed neural and reproductive system targets, it is possible that the atrial gland factor plays an hitherto unsuspected role in reproductive regulation. Moreover, the molecular similarity between the atrial gland factor and the egg-laying hormone suggests the possibility that the same humorally active species may be elaborated by two distinct tissue types.This work was supported by grants from the Medical Research Foundation of Oregon and USPHS (NS 11149). C. McC. was recipient of a Zlinkoff Research Fellowship. Dr. R. Beeman kindly confirmed our identification of the location and general morphology of the atrial gland.