DIFFERENTIAL-EFFECTS OF ARGININE VASOTOCIN AND GONADOTROPIN-RELEASING-HORMONE ON SEXUAL BEHAVIORS IN AN ANURAN AMPHIBIAN

Both arginine vasotocin (AVT) and gonadotropin-releasing hormone (GnRH ) are known to influence sexual behavior in many vertebrate taxa. We i nvestigated the effects of both of these peptides on two different sex ual behaviors, calling and amplexus, in the Great Plains toad (Bufo co gnates). AVT, at a dosage of 100 mu g/100 g toad, significantly increa sed both the amount of calling behavior per individual and the probabi lity that an individual would call. GnRH, however, had no effect on ca lling behavior. There was a reciprocal effect of these peptides on amp lexus: AVT did not induce amplexus, while GnRH significantly induced t his behavior. Furthermore, AVT-induced calling could be inhibited by M anning compound (an arginine vasopressin receptor antagonist). This is the first report of GnRH influencing sexual behavior in an anuran amp hibian. These results suggest that specific sexual behaviors in B. cog nates may be under the regulation of independent peptide control. (C) 1997 Academic Press.