Christopher Appelt's Research Page

Until recently, I was examining the urinary release of sex pheromones in the goldfish (Carassius auratus) with my advisor Peter Sorensen. The goldfish is an excellent model for examining behavioral dynamics of pheromone release because it is one of the few vertebrate species for which specific chemicals have been identified as pheromones. The first part of my research was to identify routes by which the identified sex pheromones, Prostaglandin F_{2 alpha} and 15-Keto Prostaglandin F_{2 alpha} (PGF_2a and 15K-PGF_2a, respectively), are released. We found that PGF_2a, which is a circulating hormone that stimulates female sexual (spawning) behavior (see Sorensen et al. 1995) and has a stimulatory pheromonal effect on male behavior, is released to the water by two routes, the urine and presumably the gills (See Appelt et al. 1995). More interesting, however, is that 15K-PGF_2a, a metabolite of PGF_2a that is a potent stimulatory behavioral pheromone detectable by males at 10^-12 Molar concentration, is released only in the urine (See Appelt et al. 1995).

Since 15K-PGF_2a is released only in the urine, and since it is the more potent of the two pheromones, we attempted to determine whether female goldfish release their urine (and therefore, urinary pheromones) in discrete pulses rather than in a constant stream. Thus, release of urinary pheromones may be controlled by the female. We originally tested this hypothesis by injecting radio-labelled PGF_2a into female goldfish and using estimates based on previously determined release ratios to determine the amount of radiation sufficient to indicate urinary release (See Appelt et al. 1995). While this method suggested that female goldfish release urine in discrete pulses, the evidence was still indirect and yielded very low temporal resolution. The results were published in the proceedings of the Fifth International Symposium On the Reproductive Physiology of Fish (see Appelt, C.W., P.W. Sorensen, and R.G. Kellner. 1995. Female goldfish appear to release pheromonally-active F-prostaglandins in urinary pulses. In: Proceedings of the 5th International Symposium on the Reproductive Physiology of Fish. Edited by F.W. Goetz and P. Thomas. Fish Symposium 95, Austin). If you would like to see those results now, see my poster presentation from that meeting. Click here if you would like to learn more about the meeting or order copies of the Proceedings.

More recently, I have developed a technique that allows precise, direct recording of urinary release. I can now confirm that urine is released in pulses, and I examined release of urinary pheromones with a high degree of temporal resolution. Taking advantage of this increased resolution, I have tested whether female goldfish alter urinary pheromone release in response to the presence of spawning substrate (floating vegetation), circulating PGF_2a, conspecifics (male or female), degree of sexual activity or a combination of these factors. This work is included in my M.S. thesis and will be/have been submitted for publication. Click here to see how I was able to perform these studies.

Literature Cited:
• Appelt, C.W., P.W. Sorensen, and R.G. Kellner. 1995. Female goldfish appear to release pheromonally-active F-prostaglandins in urinary pulses. In: Proceedings of the 5th International Symposium on the Reproductive Physiology of Fish. Edited by F.W. Goetz and P. Thomas. Fish Symposium 95, Austin p. 270

• Sorensen, P.W., A.R. Brash, F.W. Goetz, R.G. Kellner, L. Bowdin, and L.A. Vrieze. 1995. Origins and functions of F Prostaglandins as hormones and pheromones in the goldfish. 1996. . In: Proceedings of the 5th International Symposium on the Reproductive Physiology of Fish. Edited by F.W. Goetz and P. Thomas. Fish Symposium 95, Austin pp. 252-254

Also listed on: Russ Taylor's Goldfish Page Howard Rebel's Goldfish Page

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