2.3. Procedure of double immunofluorescence
Sections were used for double immunofluorescence to identify the areas that contained both kisspeptin and NKB immunoreactivity. Sections were washed 3 times for 5 min with phosphate buffer saline (PBS), and treated with 1% Triton X-100 in PBS for 15–20 min. Nonspecific antibody binding was reduced by treatment in 10% normal donkey serum (Golden Bridge International, Beijing, China) in PBS for 10–15 min.
Sections were incubated overnight in a mixture of pri- mary antisera: rabbit anti-kisspeptin antibody (ab19028, Abcam) at 1:400 and goat anti-NKB (sc-14109, Santa Cruz)
at a 1:500 dilution at 4 ◦ C. After washing 3 times for 5 min
in PBS, sections were immersed in donkey anti-rabbit IgG- PerCP (Golden Bridge International, Beijing, China) at 1:300 and donkey anti-goat IgG-FITC at 1:200 (Golden Bridge International, Beijing, China) and incubated for 0.5–1 h at room temperature. After rinsing with PBS, sections were mounted onto glass slides with 10% glycerol. In all reac- tions, negative controls were run in parallel by omitting the mixture of primary antisera (substituted by PBS) to demonstrate the absence of specific immunoreactivity.
Tissue sections of hypothalamus in geese were processed in the same conditions as the test slides for positive control.