Previous studies have demonstrated that ovulatory female goldfish release a variety of sex steroids into the water where they function as a pheromonal blend dominated by C21 steroids that stimulates male hormone release, sperm production and behavior. This study investigated whether male goldfish might also release sex steroids with pheromonal activity. It found that spermiated male goldfish release substantial quantities of androstenedione (AD; about 50 ng/h) together with smaller (10-20 ng/h) quantities of several other related C19 steroids but only very small quantities (<5 ng/h) of C21 steroids. Further, when sexually aroused by females and/or their pheromones, males released even greater quantities of AD (up to 1 μg/h) while C21 steroid release rate changed little. This created a ratio of C19 to C21 steroids of about 50:1 that was dramatically different from that emitted by females (1:7). The male olfactory system was also found to be extremely sensitive to AD, detecting it to near picomolar concentrations. Together with previous studies that have shown water-borne AD to increase male aggressive behavior while suppressing responsiveness to female pheromones, this study establishes AD as a male pheromone in the goldfish. Because ovulating females also release AD but in the presence of C21 steroids, recognition of the male-derived steroid pheromone is presumably mixture dependent. Crown copyright
Bibliographical noteFunding Information:
P.W.S. was supported by the National Science Foundation (BNS-9723798) and the Minnesota Agricultural Experiment Station. Chris Appelt, Jared Fine, and Kirsten Poling kindly helped with sample collection. Norm Stacey kindly reviewed an early draft of the manuscript as did two annonymous reviewers who provided some excellent suggestions. A.P.S was supported by DEFRA, U.K., M.P. was supported by the Spanish government.
Copyright 2017 Elsevier B.V., All rights reserved.
- Sex steroid