Parental fanning behavior and prolactin cell activity in the male three-spined stickleback Gasterosteus aculeatus L.

During the period that sexually mature male three-spined sticklebacks display parental fanning behavior, the rate of synthesis and release of the prolactin cells in the hypophysis, as estimated with quantitative electron microscopy, is enhanced considerably. This finding points to involvement of endogenous prolactin in the regulation of parental fanning behavior in this species.