ABSTRACT: Sex pheromones rapidly affect endocrine physiology and behaviour, but little is known about their effects on gene expression in the neuroendocrine tissues that mediate olfactory processing. In this study we exposed male goldfish for 6 h to waterborne 17,20betaP (4.3 nM) and PGF2α (3 nM), the main pre-ovulatory and post-ovulatory pheromones, respectively. Both treatments elevated milt volume (P = 0.001). Microarray hybridizations were used to male telencephalon samples following PGF2α treatment and identified 71 unique transcripts that were differentially expressed (q < 5%; 67 up, 4 down). Functional annotation of these regulated genes indicates that PGF2α pheromone exposure affects diverse biological processes including nervous system functions, energy metabolism, cholesterol/lipoprotein transport, translational regulation, transcription and chromatin remodelling, protein processing, cytoskeletal organization, and signalling. By using real-time RT-PCR, we further validated three candidate genes, ependymin-II, calmodulin-A and aldolase C, which exhibited 3 - 5 fold increase in expression following PGF2α exposure. Expression levels of some other genes that are thought to be important for reproduction were also determined using real-time RT-PCR. Expression of sGnRH was increased by PGF2α, but not 17,20betaP, whereas cGnRH expression was increased by 17,20betaP but not PGF2α. In contrast, both pheromones increase the expression of glutamate (GluR2a, NR2A) and gamma-aminobutyric acid (GABAA gamma2) receptor subunit mRNAs. This gene expression data link milt release and rapid modulation of neuronal transcription as part of the response to female sex pheromones. A total of four microarray slides were hybridized to study the effects of PGF2α on gene expression in the telencephalon. Control samples (N = 4) were pooled to form our reference or technical replicates while treatment samples (N = 4), which formed our biological replicates, were ran separately. In addition, two dye swaps were performed for our biological samples for the treatments.
