Pheromone from ovulatory female goldfish induces gonadotropin surge in males.

Characterization was made of the female stimuli which induce male gonadotropin (GtH) surge during spawning in the goldfish. In the presence of ovulatory females, olfactory tract sectioned (OTX) males failed to show sexual behavior or the GtH surge, while sham-operated (sham) males spawned and showed a GtH surge. When OTX and sham males were separated from ovulatory females with an opaque partition but with water circulating between male and female compartments, the GtH surge occurred only in sham males, although they could not court with the females. These results indicate that an olfactory stimulus (pheromone) from ovulatory females is essential to the occurrence of male GtH surge. Pheromone(s) from ovulatory female goldfish thus functions both as a releaser stimulating sexual behavior and as a primer inducing GtH surge in males.