Fig. 3. Study I: gonadotropin-releasing hormone 1 (GnRH1) gene expression differs with social state in undisturbed territorial (T) and non-territorial (NT) males. (A) The behavior of males was examined for 10 weeks to monitor social state. The social status of six males used for the NT group plotted as a function of time is shown on the left; that of T males (N=5) is shown on the right. Note that NT6 initially displayed territorial behaviors. NT/T on the vertical axis indicates that the fish exhibited a mixture of aggressive and subordinate behaviors. (B) Preoptic GnRH1 mRNA levels were measured for each individual and are plotted as optical density (OD), described in the Materials and methods and below. Note that NT6 has the highest levels of all NTs. When averaged, T males had higher levels of preoptic GnRH1 mRNA than NT males (see Fig. 4A, and Results). (C) Only GnRH1 exhibits differential expression according to social status. Phosphoimages show protected bands from three separate ribonuclease protection assays of whole-brain RNA for these 11 males. Each assay was simultaneously probed with an 18S probe (data not shown) as well as a specific probe for GnRH1, GnRH2 or GnRH3. The optical densities of the protected GnRH bands were normalized against the signal for an 18S loading control to obtain the group means reported in the text and plotted in B.

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