A variety of unnatural bile acid derivatives (9a-9f) was synthesized and used to examine the specificity with which the sea lamprey (Petromyzon marinus) olfactory system detects these compounds. These compounds are analogs of petromyzonol sulfate (PS, 1), a component of the sea lamprey migratory pheromone. Both the stereochemical configuration at C5 (i.e., 5α vs. 5β) and the extent and sites of oxygenation (hydroxylation or ketonization) of the bile acid derived steroid skeleton were evaluated by screening the compounds for olfactory activity using electro-olfactogram recording. 5β-Petromyzonol sulfate (9a) elicited a considerable olfactory response at sub-nanomolar concentration. In addition, less oxygenated systems (i.e., 9b-9e) elicited olfactory responses, albeit with less potency. The sea lamprey sex pheromone mimic 9f (5β-3-ketopetromyzonol sulfate) was also examined and found to produce a much lower olfactory response. Mixture studies conducted with 9a and PS (1) suggest that stimulation is occurring via similar modes of activation, demonstrating a relative lack of specificity for recognition of the allo-configuration (i.e., 5α) in sea lamprey olfaction. This attribute could facilitate design of pheromone analogs to control this invasive species.
Bibliographical noteFunding Information:
This work is the result of research sponsored by: (a) The Minnesota Sea Grant College Program supported by the NOAA office of Sea Grant, United States Department of Commerce , under grant no. NA07OAR4170009 . The U.S. Government is authorized to reproduce and distribute reprints for government purposes, not withstanding any copyright notation that may appear hereon. This paper is journal reprint no. JR 578 of the Minnesota Sea Grant College Program. (b) The United States National Institutes of Health ( CA-76497 ). Neither agency was involved in study design, data collection or interpretation, or writing or decision to submit this manuscript.
Copyright 2011 Elsevier B.V., All rights reserved.
- Bile acid sulfates
- Olfactory SAR
- Steroid synthesis