Social dominance in tilapia is associated with gonadotroph hyperplasia.

Highlights: [•] We produced transgenic tilapia in which FSH-secreting cells are fluorescently labeled. [•] Social status-related hormonal changes were studied in transgenic males. [•] Dominant males exhibit higher levels of gonadotropin in plasma and pituitary. [•] Dominant males show gonadotroph hyperplasia and increased cell granulation. [•] Elevated androgen levels and gonad enlargement underlie increased reproductive activity. [ABSTRACT FROM AUTHOR]